After graduating from Alabama in 1961, Fuller became an assistant coach at
Big Spring High School. In 1963, he was hired as
graduate assistant at
Oklahoma State University–Stillwater. Fuller continued his coaching career with stints at the
University of Kentucky and the
University of New Mexico. In 1974, he was appointed
defensive coordinator at
West Texas State University by
Gene Mayfield. A year later he left to take over a similar position at the
University of Wyoming under
Fred Akers. In 1977 Fuller followed Akers to the
University of Texas at Austin. Fuller instantly became a favorite among Texas fans and alumni, as his defensive units frequently ranked among the nation's best. In 1982, Fuller got his first head coaching job, replacing interim coach
Chester Caddas at
Colorado State University. He went 25–55 through seven seasons and was dismissed after the Rams finished the
1988 season at 1–10. Fuller then returned to Texas, replacing
Paul Jette as Longhorns defensive coordinator for head coach
David McWilliams. When
John Mackovic replaced McWilliams as Longhorns head coach in 1992, Fuller remained in that position as one of the only two coaches to stay and not have been fired. Two seasons later however, Mackovic fired Fuller, citing a difference of philosophy and strained relationship between the two as his reason.
Wade Phillips, Bum Phillips' son, immediately hired Fuller as
defensive backs coach for the
Denver Broncos. Returning to the high school level after 32 years, Fuller became head football coach and athletic director of the
Llano Independent School District, guiding the Yellowjackets to a 9–2 record in 1995. He then retired from coaching and left Llano to take over as athletic director at the
Austin Independent School District. ==Head coaching record==