In 1953, Blavat debuted on the original Bandstand on WFIL-TV with Bob Horn and Lee Stewart. In 1956, he managed a national tour for Danny and the Juniors, and he worked as Don Rickles' valet in 1958–59. He got his start in radio in 1960. By 1963, his show was syndicated in Camden, Atlantic City, Trenton, Pottstown, Wilmington and Allentown. He said he refused to follow a playlist, "playing music from the heart, not a research chart." During the 1960s, Blavat was a partner in the Lost Nite and Crimson record labels, along with Jared Weinstein and Collectables Records' founder Jerry Greene. Together, the three also owned Record Museum, a now-defunct chain of record stores based in Philadelphia.
From 1965–1967, Blavat produced and hosted a weekly television show in Philadelphia called The Discophonic Scene, a dance show for "all my young teens" along the lines of American Bandstand (which began in Philadelphia a decade earlier), referring to himself as "the Geator with the Heater" and "the big boss with the hot sauce." He guest-starred on television shows including The Mod Squad, The Monkees, The Tonight Show, and The Joey Bishop Show. He appeared in the movies Desperately Seeking Susan, Baby It's You, and Cookie. In 1972, Blavat purchased a nightclub in Margate, New Jersey, and named it "Memories". n 1993, Blavat was inducted into the Philadelphia Music Alliance's Hall of Fame. In 1998, he was included in the Rock & Roll Hall of Fame as part of a permanent exhibit in its Museum of Radio and Records. In 2002, he was inducted into the Broadcast Pioneers of Philadelphia's "Hall of Fame". On January 15, 2020, Blavat celebrated his 60th consecutive year on radio.
Blavat continues to broadcast on local radio seven days a week and perform at several record hops and events a week in greater Philadelphia, New Jersey, and Delaware. He has been producing oldies concerts at the Kimmel Center for the Performing Arts in Philadelphia every year since January 2002. He was a regular columnist for the Atlantic City Weekly for over 20 years and now writes his column, "Geator Gab," exclusively for the New Jersey Free Press. He has been a member of the New York Friars' Club since 2010 and has been the emcee of Time Life's annual Malt Shop Memories Cruise since 2011. His night club, Memories, where he continues to perform during the summer, has been operating steadily in Margate, New Jersey, since 1972. As of 2020, Blavat is a DJ for oldies radio station WVLT (FM) 92.1 in the South Jersey area, for the University of Pennsylvania's public radio station WXPN in Philadelphia, for radio stations WTKU-FM and WOND in Atlantic City, WBCB (AM) in Bucks County and Trenton, and WISL (AM) in Shamokin, Pennsylvania. In 2020, Jerry expanded his radio network to the internet radio station Tyme 102.9 WTYM-DB in Lutz, Florida.
On July 23, 2011, Blavat's autobiography, You Only Rock Once: My Life In Music, was published by Running Press. After its third printing it was released exactly two years later in paperback and as an audiobook in 2014.
Blavat was voted "Best Philly Icon" in a 2018 reader's poll conducted by Philadelphia magazine.