[2] In 2001–02, Harrelson helped Wayland Baptist return to the NAIA National Championships for the first time in a decade.

Harrelson earned All-Sooner Athletic Conference honors both seasons and was voted Wayland's first-ever NAIA First-Team All-American as a senior.

[8] In December 2010, Harrelson signed with the Cockburn Cougars of the State Basketball League (SBL) in Australia.

[13] In October 2012, Harrelson signed a three-year deal with the South West Slammers to be player-coach.

[8] On July 11, 2015, Harrelson was hired as head coach of the Wayland Baptist men's basketball program.

[23] In December 2021, Harrelson was named head coach of TV Langen of the German Regionalliga.

[24] On June 1, 2022, Harrelson was appointed head coach of SC Rasta Vechta of the German second division, ProA.

[27] By claiming the championship, the team earned promotion to the German top division, Basketball Bundesliga.

[28] As a newcomer to the league in the 2023-24 season, Harrelson and his Vechta outfit reached the play-off quarter final stages.