The daughter of a Danish mother and a Polish father who came to the U.S. after World War II, Cosby grew up in Greenwich, Connecticut, where she attended Greenwich High School and freelanced for the local paper. She earned her bachelor's degrees from the University of South Carolina. Cosby balanced college with a position at WACH-TV, the local FOX affiliate. After an internship with the CBS Evening News, Cosby found work as an anchor/reporter at KERO-TV in Bakersfield, California, and WBTV in Charlotte, North Carolina.

Fox News Channel

From 1995 to 2005, Cosby worked at Fox News. At Fox, she hosted both The Big Story Weekend Edition and Fox News Live with Rita Cosby.She has interviewed more than a dozen world leaders, conducting historic back-to-back interviews with Palestinian leader Yasser Arafat and Israeli Prime Minister Ariel Sharon. She was the first reporter to see prisoners held at Guantanamo Bay. She also interviewed Serbian president Slobodan Milo?evi? who called her from his prison cell at the Hague. Years earlier, while broadcasting live from Belgrade during the NATO bombing, she broke the news that three American POWs were going to be released.

Cosby also made national headlines for her interviews with boxer Mike Tyson, singer Michael Jackson and convicted serial killer David Berkowitz, "The Son of Sam," who wrote to her during the Washington, D.C. sniper shootings in October 2002. As that story unfolded, Cosby secured another major first, by reporting the names and license plate numbers of the sniper suspects. In 2001, Cosby's interview with flight attendant Anne Marie Smith led to a U.S. Attorney's Office investigation of Rep. Gary Condit for obstruction of justice and witness tampering.

Cosby served as a lead reporter during the 1996 and 2000 Presidential campaigns. During the Monica Lewinsky investigation, she broke the news that President Bill Clinton was about to be subpoenaed to testify before the grand jury.

MSNBC Television

In 2005, Cosby moved to MSNBC to host a primetime weeknight show, Rita Cosby Live & Direct. It became the network’s highest-rated show that year, and she did extensive reports for other NBC programs, including The Today Show. She traveled for the network, originating live for several weeks from New Orleans and the Gulf Coast region to report on Hurricanes Katrina and Rita, as well as from the war zone in Afghanistan and along the U.S.-Mexico border. She conducted the last broadcast interview with former Crips gang leader Stanley “Tookie” Williams and was one of a few journalists selected to witness his execution at San Quentin Prison. Additionally, she conducted rare interviews with Erik Menendez and Dr. Jack Kevorkian, both also behind bars. She left the network in 2007 to pursue other projects.

Inside Edition

Currently, Cosby is a Special Correspondent for the CBS syndicated program Inside Edition. She has been filing reports for the show since 2007, interviewing newsmakers from multiple locations across the United States.

Other media activities

In 2009, she co-hosted the worldwide broadcast of The National Memorial Day Parade simulcast to all US military installations around the globe. Well-known in the Mideast, Cosby also interviewed candidates about foreign policy on Israel's TV show, “The Ambassador.” Additionally, Cosby has co-chaired various events internationally, including the Intersec Security Conference in Dubai in 2009.

On September 4, 2007, Cosby released a book about Anna Nicole Smith, titled Blonde Ambition: The Untold Story Behind Anna Nicole Smith's Death. The book's most controversial allegation is that Smith's attorney, Howard K. Stern who claimed he fathered Smith's child Dannielynn, and Larry Birkhead, who established paternity of Smith's child, were seen in a sexually compromising position. The book also alleges that after Stern threatened to reveal Larry's sexuality, the two men reached a deal that would benefit them both following Smith's death in which Birkhead would gain custody of his daughter and Stern would remain executor of Smith’s estate. Stern threatened to file a US$60 million lawsuit against Cosby and her publisher and Birkhead threatening to follow suit. Cosby replied to the Stern lawsuit by saying "we are solid on our facts more than everwe are sure of what we have. I think it’s pretty surprising that these guys would launch some frivolous lawsuit to deflect and to smear and to intimidate and it’s not going to work." The book has become a New York Times bestseller.