The son of a prominent doctor, Gardner was born and raised in New York City. Intending to become a political scientist, he received his BA degree in Political Science from Columbia University, where he first entered the field of broadcast journalism. While working for WKCR-FM, the university's radio station, Gardner reported on student riots which occurred at Columbia in 1968.
After graduation in 1970 he began working for the news station WINS Radio in New York, and in 1972 began working for WFAS Radio in White Plains, New York, where he was quickly promoted to news director. He intended to study for a Master's degree at Brown University in 1974, but WKBW-TV in Buffalo, New York offered him a position as a news reporter, which he took.
He became the weekend anchor and substitute weekday anchor within six months. Because Buffalo had a relatively small Jewish population, he was pressured by the station's management to use a less ethnic-sounding name (this despite the fact that Goldman's boss, news director Irv Weinstein, was himself Jewish). He reluctantly began using the stage name Jim Gardner. While WKBW-TV's regular anchorman was vacationing, Gardner covered the resignation of President Richard Nixon in 1974, the first major story of his career. In January 1976 Gardner's anchoring of the station's noon news broadcast helped lead it to the top position in the market.
On June 1, 1976 Gardner became a reporter and noon anchor of WPVI-TV in Philadelphia. In November 1976 he became the anchor of the 5:30 p.m. broadcast. In 1977 he succeeded Larry Kane as the anchor of the coveted 6 p.m. and 11 p.m. time slots, a position he has held ever since. Gardner is the highest paid on-air talent in the Philadelphia broadcast market earning an annual salary of just under one million. In the May 2009 sweeps, Action News was rated # 1 in all news broadcasts beating out rivals KYW-TV and WCAU-TV in all time slots.
Important events that Gardner covered include:
- following John Cardinal Krol to Vatican City after the death of Pope Paul VI
- the return of American hostages taken during the Lebanese Civil War to Rhein-Main Air Base in West Germany
- reporting the fall of the Soviet Union from Russia
- reporting in Israel and the West Bank after the 2000 Camp David Summit
- every Democratic and Republican political convention since 1980
- interviewing every President and major presidential candidate since 1976
As main anchor, Gardner has also helped Philadelphians through the deaths of two popular
Action News personalities: Jim O'Brien in 1983 and Gary Papa in 2009.
Gardner is active in the Philadelphia metropolitan area and supports several charities. He has sponsored the Jim Gardner Scholarship for journalism and broadcasting students at Temple University (since 1987), as well as awarding the Jim Gardner Scholarship at Columbia. With the exception of 2005, he has read the Declaration of Independence aloud at Philadelphia's Independence Hall every Fourth of July.
The Broadcast Pioneers of Philadelphia selected Gardner as "Person of the Year" in 1996 and inducted him into their Hall of Fame in 2003.