A former boxer, Sullivan began his media work as a newspaper sportswriter. When Walter Winchell, one of the original gossip columnists and the most powerful entertainment reporter of his day, left the newspaper for the Hearst syndicate, Sullivan took over as theatre columnist for The New York Graphic and later for The New York Daily News. His column, 'Little Old New York', concentrated on Broadway shows and gossip, as Winchell's had and, like Winchell, he also did show business news broadcasts on radio. Again echoing Winchell, Sullivan took on yet another medium in 1933 by writing and starring in the film Mr. Broadway, which has him guiding the audience around New York nightspots to meet entertainers and celebrities. Sullivan soon became a powerful starmaker in the entertainment world himself, becoming one of Winchell's main rivals, setting the El Morocco nightclub in New York as his unofficial headquarters against Winchell's seat of power at the nearby Stork Club. Sullivan continued writing for The News throughout his broadcasting career and his popularity long outlived that of Winchell.

In 1948, the CBS network hired Sullivan to do a weekly Sunday night TV variety show, Toast of the Town, which later became The Ed Sullivan Show. Debuting in June 1948, the show was broadcast from CBS Studio 50, at 1697 Broadway (at 53rd Street) in New York City, which in 1967 was renamed the Ed Sullivan Theater (and is now the home of The Late Show with David Letterman).

Television critics gave the new show and its host poor reviews. Harriet Van Horne alleged that "he got where he is not by having a personality, but by having no personality." (The host wrote to the critic, "Dear Miss Van Horne: You bitch. Sincerely, Ed Sullivan.") Sullivan had little acting ability; in 1967, 20 years after his show's debut, Time magazine asked "What exactly is Ed Sullivan's talent?" His mannerisms on camera were so awkward that some viewers believed the host suffered from Bell's palsy. Time in 1955 stated that Sullivan resembled

a cigar-store Indian, the Cardiff Giant and a stone-faced monument just off the boat from Easter Island. He moves like a sleepwalker; his smile is that of a man sucking a lemon; his speech is frequently lost in a thicket of syntax; his eyes pop from their sockets or sink so deep in their bags that they seem to be peering up at the camera from the bottom of twin wells.

The magazine concluded, however, that "Yet, instead of frightening children, Ed Sullivan charms the whole family." Sullivan appeared to the audience as an average guy who brought the great acts of show business to their home televisions. ("Ed Sullivan will last", comedian Fred Allen said, "as long as someone else has talent", and frequent guest Alan King said "Ed does nothing, but he does it better than anyone else in television.") He had a newspaperman's instinct for what the public wanted, and programmed his variety hours with remarkable balance. There was something for everyone. A typical show would feature a vaudeville act (acrobats, jugglers, magicians, etc.), one or two popular comedians, a singing star, a hot jukebox favorite, a figure from the legitimate theater, and for the kids, a visit with puppet "Topo Gigio, the little Italian mouse." The bill was often international in scope, with many European performers augmenting the American artists.

Sullivan had a healthy sense of humor about himself and permitted...even encouraged...impersonators such as John Byner, Frank Gorshin, Rich Little and especially Will Jordan to imitate him on his show. Johnny Carson also did a fair impression, and even Joan Rivers imitated Sullivan's unique posture. The impressionists exaggerated his stiffness, raised shoulders, and nasal tenor phrasing, along with some of his commonly used introductions, such as "And now, right here on our stage..." and "For all you youngsters out there..." and "...a really big shoe..." (his pronunciation of the word "show"). Will Jordan portrayed Sullivan in the films I Wanna Hold Your Hand, The Buddy Holly Story, The Doors, Mr. Saturday Night, Down With Love, and in the 1979 TV movie Elvis.

In the 1950s and 1960s, Sullivan was a respected starmaker because of the number of performers that became household names after appearing on the show. He had a knack for identifying and promoting top talent and paid a great deal of money to secure that talent for his show.

Sullivan appreciated African American talent. He paid for the funeral of dancer Bill 'Bojangles' Robinson out of his own pocket. He also defied pressure to exclude African American musicians from appearing on his show. In 1969, Sullivan presented the Jackson 5 with their first single "I Want You Back", which ousted B. J. Thomas's "Raindrops Keep Falling on My Head" from the top spot of Billboard's pop charts.

There was another side to Sullivan: he could be very quick to take offense if he felt he had been crossed, and could hold a grudge for a long time. This could unfortunately be seen as a part of his TV personality. Jackie Mason, Bo Diddley, Buddy Holly, and The Doors became intimately familiar with Sullivan's negative side.

On November 20, 1955, Bo Diddley was asked by Sullivan to sing Tennessee Ernie Ford's hit "Sixteen Tons". Come air time, Diddley sang his #1 hit song "Bo Diddley". He was banned from the show.

On January 26, 1958, for their second appearance on The Ed Sullivan Show, Buddy Holly and the Crickets were scheduled to perform two songs. Sullivan wanted the band to substitute a different song for their record hit "Oh, Boy!", which he felt was too raucous. Holly had already told his hometown friends in Texas that he would be singing "Oh, Boy!" for them, and told Sullivan as much. During the afternoon the Crickets were summoned to rehearsal at short notice, but only Holly was in their dressing room. When asked where the others were, Holly replied, "I don't know. No telling." Sullivan then turned to Holly and said "I guess The Crickets are not too excited to be on The Ed Sullivan Show" to which Holly caustically replied, "I hope they're damn more excited than I am." Sullivan, already bothered by the choice of songs, was now even angrier. He cut the Crickets' act from two songs to one, and when introducing them mispronounced Holly's name, so it came out vaguely as 'Hollered' or "Holland." He also pronounced Holly's backing band as what sounded like "The Picketts". In addition, Sullivan saw to it that the microphone for Holly's electric guitar was turned off. Holly tried to compensate by singing as loudly as he could, and repeatedly trying to turn up the volume on his guitar. For the instrumental break he cut loose with a dramatic solo, making clear to the audience that the technical fault wasn't his. The band was received so well that Sullivan was forced to invite them back for a third appearance. Holly's response was that Sullivan didn't have enough money. Film of the performance survives; photographs taken that day show Sullivan looking angry and Holly smirking and perhaps ignoring Sullivan.

In 1961, Bob Dylan was to appear but was banned from the show for insisting on singing the controversial "Talking John Birch Society Blues" even though Sullivan backed him up. Other artists would sing covers of Dylan songs on the show in the coming years.

Jackie Mason was banned from the series in October 1964 (the ban was removed a year and a half later, and Mason made his final appearance on the show). During Mason's monologue Sullivan, off camera, gestured that Mason should wrap things up, as a breaking news story was developing. The nervous Mason told the audience, "I'm getting two fingers here!" and made his own frantic hand gesture: "Two fingers for you!" Videotapes of the incident are inconclusive as to whether Mason's upswept hand was intended to be an indecent gesture, but Sullivan's body language immediately afterward made it clear that he was convinced of it, despite Mason's panic-stricken denials later. Sullivan later invited Mason back for a return engagement, but the notoriety of the "finger" incident lingered with the studio audience.

When The Byrds performed on December 12, 1965, David Crosby got into a shouting match with the show's director. They were never asked to return.

On January 15, 1967 The Rolling Stones were told to change the chorus of "Let's Spend the Night Together" to "Let's spend some time together". Lead singer Mick Jagger complied, but deliberately called attention to this censorship by rolling his eyes and mugging when he uttered the new words. Shortly, after the performance, the Stones went backstage, and came back on stage, dressed in Nazi uniforms with swastikas, which caused an angry Sullivan to tell them to go back to their dressing rooms and change back into their performing outfits, however, the Stones left the studio and Sullivan banned the group from ever appearing on his show again.

The Doors were banned on September 17, 1967 after they were asked to remove the lyric "Girl, we couldn't get much higher" from their song "Light My Fire" (CBS censors believed that it was too overt a reference to drug use) and were asked to change the lyrics "girl we couldn't get much better". But lead singer Jim Morrison sang the song with the lyrics intact.

Moe Howard of the Three Stooges recalled in 1975 that Sullivan had a memory problem of sorts: "Ed was a very nice man, but for a showman, quite forgetful. On our first appearance, he introduced us as the Three Ritz Brothers. He got out of it by adding, "who look more like the Three Stooges to me." Diana Ross later recalled Sullivan's forgetfulness during the many occasions The Supremes performed on his show. In a 1995 appearance on The Late Show with David Letterman (which is filmed in Ed Sullivan Theater), Ross stated, "he could never remember our names. He called us 'the girls'."

In a 1990 Press conference Paul McCartney recalled meeting Sullivan in the early 1970's and that Sullivan had no idea who he was. Trying to remind him that he was one of The Beatles Sullivan still obviously could not remember and, either out of politeness or wanting to get away, shook McCartney's hand and left.

Unlike many shows of the time, Sullivan asked that most musical acts perform their music live, rather than lip-synching to their recordings. Some of these performances have recently been issued on CD. Examination of performances show that exceptions were made, as when a microphone could not be placed close enough to a performer for technical reasons. An example was B.J. Thomas' 1969 performance of "Raindrops Keep Fallin' on My Head," in which actual water was sprinkled on him as a special effect.

The act that appeared most frequently through the show's run was the Canadian comedy duo of Wayne & Shuster, making 67 appearances between 1958 and 1969.

Sullivan also appeared as himself on other television programs, including an April 1958 episode of the Howard Duff and Ida Lupino CBS sitcom, Mr. Adams and Eve.

On September 14, 1958 Sullivan appeared on What's my Line? as a mystery guest and showed his comedic side by donning a rubber mask.

In 1961, Sullivan was asked by CBS to fill in for an ailing Red Skelton on The Red Skelton Show. He performed some of Skelton's characters successfully. One character was renamed "Eddie the Freeloader" (normally "Freddie the Freeloader").

In August 1956, Sullivan was injured in an automobile accident that occurred near his country home in Southbury, Connecticut. Sullivan had to take a medical leave from the show and missed the September 8 appearance of Elvis Presley. Earlier Sullivan had said that he would never invite Presley on his program. Charles Laughton wound up introducing Presley on the Sullivan hour. On a later Presley appearance, Sullivan made amends by telling his audience, "This is a real decent, fine boy."

Sullivan's failure to scoop the TV industry with Presley made him determined to get the next big sensation first. In 1964, he achieved that with the first live American appearance of The Beatles, on February 9, 1964, the most-watched program in TV history to that point and still one of the most-watched programs of all time. The Beatles appeared three more times on the Sullivan show in person, and submitted filmed performances later. Sullivan struck up such a rapport with the Beatles that he agreed to introduce them at their momentous Shea Stadium concert on August 15, 1965. The Dave Clark Five, heavily promoted as having a "cleaner" image than the Beatles, made 13 appearances on the Sullivan show, more than any other UK group.

In the fall of 1965, CBS began televising the weekly programs in color. Although the Sullivan show was seen live in the Central and Eastern time zones, it was taped for airing in the Pacific and Mountain time zones. Most of the taped programs (as well as some early kinescopes) were preserved, and excerpts have been released on home video.

At a time when television had not yet embraced country and Western music, Sullivan was adamant about featuring Nashville performers on his program. This insistence paved the way for shows such as Hee Haw and variety shows hosted by country singers like Johnny Cash and Glen Campbell.

Reacting to the Cold War fervor of the 1950s, Ed Sullivan worked closely with Theodore Kirkpatrick of the anti-communist Counterattack newsletter. Sullivan would check with Kirkpatrick if a potential guest had some "explaining to do" about his politics. Sullivan wrote in his June 21, 1950 New York Daily News column that "Kirkpatrick has sat in my living room on several occasions and listened attentively to performers eager to secure a certification of loyalty." Jerome Robbins, in his PBS American Experience biography, explained that he was forced to capitulate to the House Un-American Activities Committee, identifying eight Communist sympathizers and disgracing himself among his fellow artists, because Sullivan threatened to reveal Robbins's homosexuality to the public.

By 1971, the show was no longer in television's top 20. New CBS executives, who wanted to attract younger viewers, canceled the show along with virtually all of the network's oldest shows. Sullivan was so upset and angry that he refused to do a final show, although he did return to CBS for several TV specials and a 25th-anniversary show in 1973.

One year later, on October 13, 1974, Ed Sullivan died of esophageal cancer at age 73 at New York's Lenox Hill Hospital. His funeral was attended by 3,000 at St. Patrick's Cathedral, New York on a cold, rainy day. Sullivan is interred in a crypt at the Ferncliff Cemetery in Hartsdale, New York.

Sullivan was engaged to champion swimmer Sybil Bauer, but she died of cancer in 1927 at the age of 23. He was married to the former Sylvia Weinstein from April 28, 1930, until her death on March 16, 1973. They had one daughter, Betty Sullivan (who married the Sullivan show's producer, Bob Precht). Sullivan was in the habit of calling Sylvia after every program to get her immediate critique.

Sullivan has a star on the Hollywood Walk of Fame at 6101 Hollywood Blvd.