Scott began umpiring at age 15 and entered the minor leagues in 1981, eventually working his way up to the Triple-A American Association.

When the AL introduced red shirts in 1996, Scott frequently was the only umpire to wear the color, rather than the usual navy blue.

He almost always wore the red shirt when working home plate, including Game 3 of the 1998 World Series at Qualcomm Stadium.

In 1991 MLB revised the rules relating to official no-hit games, requiring that a pitcher must complete a minimum of 9 innings, and thereby voiding Hawkins' effort.

Scott was the first base umpire when Detroit Tigers pitcher Justin Verlander threw a no-hitter at Comerica Park against the Milwaukee Brewers on June 12, 2007.

[8] Scott was the third base umpire when six Seattle Mariners pitchers combined to no-hit the Los Angeles Dodgers on June 8, 2012.

[10] Scott was the crew chief for the 2015 American League Division Series between the Toronto Blue Jays and Texas Rangers.

After a consultation with the other umpires, Scott reversed the decision and allowed the run to count on the grounds that Choo didn't intentionally interfere with the throw, and therefore the play was live.

Hale was acting as the Blue Jays’ manager due to the ejection of John Gibbons (along with first base coach Tim Leiper) earlier in the game.

[16] In 2022, Scott published his memoir The Umpire Is Out: Calling the Game and Living My True Self, co-written with Rob Neyer.