[3] As a young man, Gumbel grew up on Chicago's South Side, where he was raised Catholic, attending and graduating from De La Salle Institute.

[7] He had two sisters, Renee Gumbel-Farrahi and Rhonda Gumbel-Thomas, and a younger brother, Bryant Gumbel, who also pursued a network television broadcasting career.

[8][9] In 1973, Greg's brother Bryant, then working as a television sportscaster at KNBC in Los Angeles, informed him that another NBC owned-and-operated station, WMAQ-TV in Chicago, was auditioning for a sports announcer.

[10] Prior to his rising to prominence at CBS, Gumbel worked for MSG, ESPN, and WFAN radio in New York City.

On MSG, Gumbel served as a backup announcer for Marv Albert on New York Knicks broadcasts as well as providing coverage for college basketball.

After MSG signed a large contract to broadcast New York Yankees games the same year, Gumbel served as host of the pregame and postgame shows.

[13] Besides his hosting duties, Gumbel provided play-by-play for the NBA (alongside Quinn Buckner), Major League Baseball including the 1993 American League Championship Series (alongside Jim Kaat), and College World Series baseball.

[23] CBS Sports extended its contract with Gumbel on March 15, 2023, which allowed him to continue hosting college basketball while stepping back from NFL coverage.

[1][5][29][30] Gumbel is one of a few sports announcers to have worked on pre-game, play-by-play, and radio Super Bowl broadcast teams.

[5] During his tenure as the chief anchor of The NFL Today, he served alongside co-anchors Dan Marino, Shannon Sharpe, and Boomer Esiason.