George Horton was an assistant at Cerritos in 1976-1977 and at Los Angeles Valley College in 1978-1980. He went back to Cerritos as assistant through 1984, then took over as head coach in 1985.
Horton was an assistant at Cal State Fullerton under Augie Garrido from 1991 to 1996, and served as head coach there from 1997 through the 2006 season. He led the Titans to five College World Series appearances and the 2004 national title. On September 1, 2007 he accepted the head coaching job at the University of Oregon, a Pac-10 school that was reinstating baseball after a twenty six year absence. The Ducks resumed play under his leadership in the 2009 season and he remained there through 2019. Horton planned to sit out the 2020 season, but agreed to join the Orange Coast College staff after head coach John Altobelli passed away in a helicopter accident. Altobelli's son, J.J. Altobelli, had played and coached for Horton at Oregon.