Farrell, a Seattle native, joined the coaching staff prior to the start of the 2023 season after previously being the head coach of Ballard FC of USL League 2. He led Ballard to an 8-2-2 regular season in their inaugural season, before guiding the team to a playoff run that saw them reach the Western Conference Finals. The team clinched their second straight playoff berth before Farrell stepped down in 2023.

Despite starting his professional coaching career with the Sounders in 2006, Farrell first served as an assistant coach with the Seattle U program back in 2005. The Redhawks went 13-6-0 that season, finishing first in the GNAC. 

Prior to his career in coaching, Farrell had a successful career as a player. After graduating from Shorecrest High School, he attended the University of Washington and Seattle Pacific University. Post college he joined the Seattle Sounders - then of the USL - where he spent three seasons while appearing in 69 games. He was drafted by the Columbus Crew in the 1997 MLS Supplemental Draft, spending four seasons with the club. In all, he spent 11 seasons with five different clubs.