Nantz started as an anchor and sportscaster for KHOU in Houston, Texas in the early 1980s and then became a weekend sports anchor on KSL-TV in Salt Lake City (1982–1985) where he called BYU football games and Utah Jazz games along with Hot Rod Hundley.[8][9]
Nantz joined CBS Sports in 1985, initially working as a studio host for the network's college football and basketball coverage, and as an on-course reporter for PGA Tour golf, as well as calling NFL games on Westwood One (from 1988 to 1990, when he was moved to television, Nantz called Sunday Night Football games for what was then called CBS Radio Sports). Nantz has anchored CBS' coverage of the Masters Tournament since 1989. Following Brent Musburger's ouster from CBS in 1990, Nantz moved into the lead play-by-play role on the NCAA Final Four men's basketball finals, working with Billy Packer (1991-2008), Clark Kellogg (2009-2013), Steve Kerr (2010-2013), and Greg Anthony (2013-2014). Nantz's most recent partners on March Madness coverage were Bill Raftery and Grant Hill.[10] In October 2022, Nantz announced his intention to step away from basketball coverage to spend time with family and will be replaced by Ian Eagle.[11]
Nantz opens each of his broadcasts by saying, "Hello, friends". The greeting came about as a way for Nantz to identify himself to his father, who had been suffering from Alzheimer's disease.[12]
Nantz’s broadcast style includes a penchant for informing listeners of historical facts or statistics regarding athletes or situations as a competition progresses.
After hosting CBS's pre-game program The NFL Today from 1998 to 2003, he became The NFL on CBS' top play-by-play announcer in 2004. That move sent Greg Gumbel to the studio, and Nantz to the stadium booth with Phil Simms. In 1991 and 1992, Nantz, like Tim Brant, was paired with analyst Hank Stram on NFL broadcasts. In 1993, he had previously filled-in for his predecessor, Greg Gumbel as NFL Today host while Gumbel was away covering the American League Championship Series for CBS. Verne Lundquist and Dan Fouts were the #2 team for much of the 1993 season. However, Nantz and Randy Cross would call the second round playoff game for CBS (Dallas vs. Green Bay) not called by Pat Summerall and John Madden. Meanwhile, Tim Ryan and Matt Millen were the #3 team for much of the 1993 season.
On February 4, 2007, Nantz called the play-by-play of Super Bowl XLI. He joins Curt Gowdy, Kevin Harlan, and Dick Enberg as the only play-by-play announcers to ever call both a Super Bowl and an NCAA Men's Basketball Championship Game. (Greg Gumbel called CBS's previous Super Bowls, Super Bowl XXXV and Super Bowl XXXVIII.) Nantz is also one of two men to host a Super Bowl, announce an NCAA Men's Basketball Championship game, and host coverage of The Masters from Butler Cabin with Brent Musburger being the other. Musburger also accomplished all three feats with CBS. During Super Bowl XLVII, Joe Flacco unknowingly hit Nantz with the Vince Lombardi Trophy during the presentation, but Nantz simply brushed it off.
In 2014, Nantz and broadcast partner Phil Simms called Thursday Night Football games in a deal with CBS and the NFL Network. Tracy Wolfson was the sideline reporter for the Thursday games along with the Sunday games on CBS. In 2017, former Dallas Cowboys quarterback Tony Romo replaced Phil Simms as Nantz's color commentator for CBS' NFL telecasts.[13]
Nantz and Romo called Super Bowl LIII in 2019 and Super Bowl LV in 2021. On January 9, 2022, Tom McCarthy filled in for Nantz for a Week 18 game featuring the Carolina Panthers and Tampa Bay Buccaneers.[14] Nantz, like Romo the year before, had to sit out of the final week of the regular season due to COVID protocols.
Nantz has appeared on episodes of The Price Is Right to present a Showcase prize that involves CBS Sports properties, one to attend the 2009 Final Four in Detroit and another in 2010 for Super Bowl XLIV (with Phil Simms),[15] as part of changes to the long-time game show to use product placement models and CBS crossovers, including sports packages. Nantz appeared as himself in the 1996 film Tin Cup[16] and has appeared in episodes of several television series including Arliss, Yes, Dear, Criminal Minds, and How I Met Your Mother (season 5, episode 14 + 15 and season 9, episode 24). He portrayed the announcer for the fictional baseball team in the short-lived series Clubhouse, and his voice can be heard in the 1998 film Scrapple. He also appeared in Fantasy Football, a film produced by CBS' sister network Nickelodeon.[17]
Since 2009, Nantz has guest commentated on the final round of The Open Championship for the BBC.[18]
Nantz teamed with Gary McCord to provide extensive commentary in the 1999 PC golf game Jack Nicklaus 6: Golden Bear Challenge, and his commentary is featured in the Golden Tee Golf arcade game series. From 2012 until 2016 (when they were replaced with Brandon Gaudin and Charles Davis), Nantz, along with Phil Simms, provided commentary for the Madden NFL series. In 2013, Nantz appeared in a Papa John's Pizza ad with Peyton Manning, quarterback of the Denver Broncos, and founder John Schnatter. He has also been part of Capital One's March Madness ad campaign featuring Charles Barkley, Samuel L. Jackson, and Spike Lee.[19]