The moves end a difficult seven-week search for Buffaloes coach Mike MacIntyre, who is trying to fix a defense that was one of the worst in the FBS this past season. Former defensive coordinator Kent Baer and defensive ends coach Andy LaRussa accepted jobs at UNLV this past December.
Leavitt, 58, spent the last four seasons as linebackers coach for the San Francisco 49ers and is renowned for having tough defenses. He had a 95-57 record as coach at South Florida in 13 seasons, but was fired in 2010 after a university investigation determined he struck a player in the locker room and didn't tell the truth about the incident.
Leavitt started South Florida’s program from scratch in 1996. He had previously been an assistant at Kansas State for six years, first as linebackers coach before adding co-defensive coordinator duties his last five seasons.
He was a graduate assistant at Iowa in 1989 after being a defensive assistant at Morningside College for six years. He was also defensive coordinator at Dubuque from 1980-81 and a graduate assistant for two years before that at his alma mater, Missouri.
The hiring of the 43-year-old Tumpkin, as first reported by SI.com, comes after he spent the last five seasons as defensive coordinator at Central Michigan, where he resigned his position on Wednesday. Under him, the Chippewas were 29th in the FBS in total defense this past year (355.5 yards per game).
Tumpkin coached linebackers at Pittsburgh (2008-09) and at SMU (2005-07). Before that, he was linebackers and secondary coach at Sam Houston State for three years and defensive coordinator at Lakeland College from 2000-01.
He was linebackers coach and recruiting coordinator at Southern Illinois from 1998-99 and a graduate assistant the previous year at Western Michigan. His resume also includes one-year stops at Defiance College (1996), Northern Michigan (1995) and Lakeland (1994).
This next season is critical for MacIntyre. In his two seasons at Colorado, he has a 6-18 record, which included a winless mark in the Pac-12 this season during a 2-10 campaign.