As a young player in New York, he studied the games of Knicks stars Walt Frazier and Earl Monroe while admiring Larry Bird and wearing #17 in honor of John Havlicek.

[4] As a youth, he regularly traveled to the Bronx and Harlem, in predominantly Black neighborhoods, to play against the best basketball players in New York City.

[7] Mullin was recruited by the Hall of Fame coach Lou Carnesecca to play for St. John's University[6] in nearby Queens.

[9] In Mullin's first three seasons with the Warriors, he was primarily a spot-up shooting guard playing in the backcourt alongside Eric "Sleepy" Floyd.

In his second season, 1986–87, the Warriors advanced to the Western Conference semifinals under George Karl, where they lost to the eventual NBA champion Los Angeles Lakers.

Mullin was a five-time All-Star during his time in Golden State and won his second Olympic gold medal in 1992 as a member of the Dream Team.

Mullin was traded after the 1996–97 season to the Indiana Pacers for second-year center Erick Dampier and NBA journeyman Duane Ferrell.

As a member of the Indiana Pacers, Mullin, who was primarily a bench player at this time, appeared in three games of the 2000 NBA Finals against the Los Angeles Lakers and scored four points total.

[citation needed] According to Jim O'Brien, Mullin was similar to NBA legend Larry Bird because both players lacked speed, had a great outside shot and had the innate ability to put their defender off guard.

Mullin also won gold medals in the 1992 Tournament of the Americas with the "Dream Team", the 1984 Summer Olympics, the 1983 Pan American Games, the 1982 Jones Cup, and the 1982 Seoul Invitational.

On April 9, 2019, Mullin resigned as head coach after compiling a 59–73 record in four seasons, including 20–52 in Big East play, citing a "personal loss" which was widely seen as the death of his brother.

[22] As an advisor, Mullin's duties were not only to provide advice to Ranadive and D'Alessandro on player transactions, but to also supervise the organization's college and overseas scouting program.

[25] In December 2011, Mullin worked with the ESPN broadcasting crew for Mark Jackson's coaching debut with the Golden State Warriors.

Mullin joined his former television colleagues, Jeff Van Gundy and Mike Breen to announce the game against the Los Angeles Clippers in the season opener and Christmas finale.

[26] In September 2019, after leaving St. John's University, Mullin was announced as a pregame and postgame studio analyst for Warriors games on NBC Sports Bay Area.

On November 19, 2004, the Warriors, Mullin and his former teammates Mitch Richmond and Tim Hardaway participated in the fantasy camp named "Run With TMC".

[37] In July 2014, Mullin was featured at a wheelchair basketball charity and opportunity event hosted in Puerto Rico by Max International.