Smith was born in Fort Worth, Texas. She married her college sweetheart, George Edward Beeman, a World War IIbombardier, in 1944. But she left him to enroll in the University of Texas where all her papers and memorabilia are in the Dolph Brisco Center. They were divorced several years later.
On February 16, 1976, Smith began a self-titled gossip column for the New York Daily News. During a 1979 newspaper strike, her Daily News editors asked her to appear daily on WNBC-TV's Live at Five, and she stayed with the program for eleven years. Her exposure on television made Smith a popular figure on the Manhattan social scene and provided fodder for her column, which had, by then, been syndicated to nearly seventy newspapers. She won an Emmy for her reporting on Live at Five for WNBC in 1985.
In 1991 Smith, shortly after her exclusive interviews with Ivana Trump at the time of her divorce from real-estate tycoon Donald Trump, moved to Newsday, where she stayed until 1995. Smith then signed on to the Murdoch-owned New York Post. She worked for Fox News for seven years and is now on Fox & Friends. She is the only columnist to ever have her column printed in three major New York City papers at the same time.
In April 2005, Smith left Newsday, over a contract dispute. The official discontinuation of her column came after several months of dispute among Smith, her lawyer David Blasband, and Newsday management. The matter was settled out of court and Smith continued at the New York Post and the Staten Island Advance, where her column still appeared.
On February 24, 2009, the Post announced that the paper would stop running Smith's column effective February 26, 2009, as a cost-cutting measure.
Smith acknowledged her bisexuality (or as she refers to it, "gender neutrality") in her memoirs. But in the December 5, 2000 issue of The Advocate, Smith dug deeper and confided in Editor in Chief, Judy Wieder, that it isn't her nature to be a role model in the LGBT movement. However she admitted: "I think that my relationships with women were always much more emotionally satisfying and comfortable [than with men]. And a lot of my relationships with men were more flirtatious and adversarial. I just never felt I was wife material. I always felt that I was a great girlfriend."  She is twice-divorced and currently resides alone in an apartment in Manhattan's Murray Hill neighborhood. She was a good friend of former Texas Governor Ann Richards, and helped her to acculturate to New York City society after Richards left Texas.
She has raised millions of dollars for charities, $6 million for Literacy Partners, millions for AmFAR, the New York Landmarks Conservancy, PAL. and a lot of money for the Mayor's Fund to Advance New York City under Mayor Mike Bloomberg.