Sinclair was born in Detroit, Michigan, but his family moved to Champaign, Illinois, in 1989.[1][2] He attended the University of Illinois Urbana-Champaign, but left before graduating to pursue a career in radio.[2] In 2001, he was working in local radio in Huntsville, Alabama, when he was appointed as the public address announcer for the Huntsville Flight of the NBA Development League.[1] In 2011, Sinclair reached the final four out of 3,000 applicants to take over as the PA announcer for the Chicago Cubs.[1] In 2012–13, Sinclair started working as the announcer for the Fighting Illini women's basketball team, finishing in 2021–22 after 10 seasons. In 2015, he transferred over to the men's team.[3]
In 2018, after a five-game stint that summer with the Indiana Fever WNBA team, he was named as the announcer for the Indiana Pacers NBA franchise, whom he had watched as a child and where his family were now living.[1] He held the role for two seasons from 2018–19 to 2019–20 before leaving to join the Bulls ahead of the 2020–21 season, where he replaced long-serving announcer Tommy Edwards.[4] He began with the Bears in 2020, taking over from 37-year veteran announcer Jim Riebandt.[2]
Sinclair served as the public address announcer for the NBA All-Star Game in Chicago in 2020, in Cleveland for the league's 75th season in 2022, in Salt Lake City in 2023, and in Indianapolis in 2024.[5] He was also one of four public address announcers for the 2020 NBA Bubble at Walt Disney World in Florida for a five-week spell, followed by four weeks in the Wubble at IMG Academy in Bradenton, Florida, before leaving to commence his announcing duties for the Chicago Bears at Soldier Field.[2][6] Starting in 2021, the video game NBA 2K22 included the real public address announcer for all 32 NBA teams for the first time; Sinclair serves as the in-game announcer for Bulls home games, and has been featured in every subsequent edition.[7] In 2024, Sinclair featured in a commercial for State Farm alongside Benny the Bull.[8]