San Francisco, New York City and NBC
Tompkins was born and raised in San Francisco. He began his broadcasting career as a writer and producer for San Francisco radio station KCBS in 1965, before being hired as sports director at the local CBS television affiliate, KPIX-TV. Since then he has spent five years at NBC, ten years at HBO, eight years at ESPN, and the past fourteen years at Fox Sports.
In 1974, he moved to New York to join WNBC-TV as a sports anchor and feature reporter, before moving to NBC Sports in 1975 to host weekly radio shows as well as television play-by-play for basketball and football.
Tompkins returned to San Francisco in 1978 and joined then-NBC affiliate KRON-TV as sports director, while continuing to cover Pac-10 basketball for NBC as well as feature stories for its NFL pre-game show. He left KRON in 1980 to join the then-fledgling cable channel HBO.
In 2013, he joined the faculty at Dominican University of California as a professor for the university's Communications Department.
At HBO, Tompkins came into much greater national prominence alongside Larry Merchant and Sugar Ray Leonard as a member of the HBO Boxing show's team. He called fights at HBO for many years and some of his commentaries became famous, such as his call when Alexis Argüello was hurt by Aaron Pryor in round fourteen of their Battle of the Champions (Arguello...oh! Arguello is hurt!!), when Héctor Camacho was buckled by Edwin Rosario in round five of their fight (Camacho had never been hurt before!) and when Mike Tyson won the WBC world Heavyweight title with a second-round knockout of Trevor Berbick (And we have a new era in boxing.). In 1992, he won the Sam Taub Award for excellence in boxing broadcasting journalism. Tompkins also co-hosted HBO's baseball program, Race for the Pennant.
Acting career and ESPN
Tompkins made his acting debut in 1985, when he portrayed a USA Network sportscaster during the Rocky Balboa-Ivan Drago fight in Rocky IV. Later he moved to the ESPN network, where he did play-by-play on Thursday Night Fights alongside Al Bernstein. He also did college basketball, The French Open and many other tennis tournaments, the Tour De France, World Track and Field and Swimming and Diving Championships as well as the World Gymnastics Championships. During that time he continued to be "The Voice" of Pac 10 (now 12) Conference football for various syndicators.
In 1995 Tompkins left ESPN to join Fox Sports as the play-by-play announcer of Sunday Night Fights, and he traveling through the United States alongside Sean O' Grady and Rich Marotta. Tompkins continued as the lead play-by—play commentator of FSN's coverage of Pac-12 football with Petros Papadakis and basketball with Dan Belluomini, Marques Johnson, Don McClean and Ernie Kent through 2011. He also commentated much of FSN's poker coverage, including the Aussie Millions and Poker Dome Challenge. .
WAC Sports Network
In July 2011 it was announced that Tompkins would leave Pac-12 football broadcasts and instead be the new play-by-play man for the WAC Sports Network, going into its second season. Tompkins' fight duties and college basketball games with FSN continued. Tompkins called nine broadcasts with Joe Glenn during the 2011 season.
Showtime sports and Time Warner Sports Network
The WAC Sports Network folded after 2011 allowing Tompkins to become a free agent in terms of college football sports broadcasting for 2012. He was hired by the Mountain West Conference to serve as their #1 play-by-play broadcaster for the new MWC regional package on Time Warner Cable SportsNet (started after Mtn folded after spring 2012). He was assigned Jay Leeuwenburg as his color analyst.
Tompkins joined Showtime Sports on February 18, 2012, as blow-by-blow voice of the network's ShoBox series and ShoExtreme series with veteran analyst Steve Farhood.
He continues to do college football and basketball for Time-Warner Network and Comcast.