He played 17 seasons in Major League Baseball (MLB) with the Kansas City Royals, the Milwaukee Brewers, and the Toronto Blue Jays.

[1] On December 16, 1968, the Astros traded Martinez to the Kansas City Royals alongside Mike Sinnerud and Tommy Smith in exchange for Johnny Jones.

During a meeting, as Bouton's team is devising strategies to effectively pitch to their opponents, manager Joe Schultz lacks any concrete suggestions about the rookie Martinez, and famously advises that they just "zitz" him.

[1] Martinez's career took a bad turn when he broke his leg and severely dislocated his ankle in a home plate collision with the Seattle Mariners' Phil Bradley at the Kingdome on July 9, 1985.

[10] However, he was tagged out by a sprawled-out Martinez, who despite having a broken leg had managed to catch the return throw from George Bell on the ground, thus completing a 9–2–7–2 double play.

[11] After retiring as an active player following the 1986 season, Martinez began his broadcasting career as a color analyst for Toronto Blue Jays games in 1987.

[13] The pair of Hughson and Martinez also worked together on a number of ESPN telecasts, as well as on EA Sports Triple Play Baseball video game series.

During his stint on ESPN, Martinez won a Sports Emmy Award for his work as part of the crew for the broadcast of Cal Ripken’s 2,131st consecutive game.

[15] For the 2003 to 2009 seasons, he was the color commentator for Baltimore Orioles television broadcasts, alongside play-by-play announcers Jim Hunter and Gary Thorne on the Mid-Atlantic Sports Network.

[16] From 2005 to 2009, Martinez was a co-host of XM Radio's Baseball This Morning show on the MLB Home Plate channel and contributed color commentary for Sunday afternoon games and on TBS, as well as for the network's postseason coverage.

[17] In late April 2009, Buck substituted for the ill Jerry Remy as commentator for the three game Red Sox–Rays series for NESN.

With Shulman's part-time return to the Blue Jays broadcast team in 2016, Martinez now splits duties between play-by-play and color analyst.

Martinez and his wife Arlene have one son Casey, a 47th round pick (1,384th overall) by Toronto in the 2000 Major League Baseball draft.