After three years on the Boilermaker staff, Lavin returned to California when UCLA head coach Jim Harrick hired him as an assistant in 1991.

Later that season on February 11, 1997, with the Bruins tied for first place in the Pac-10 with an 8–3 record, UCLA removed the "interim" tag from Lavin's title and formally named him as its 11th head coach.

The Bruins then won their next 11 games en route to the Pac-10 title, before being eliminated by the Minnesota Gophers in the NCAA Midwest Regional Final.

The Red Storm posted a 7–1 record at Madison Square Garden and saw its home attendance climb by 38.1 percent, marking the fourth-largest increase in NCAA Division I men's basketball.

Lavin underwent treatment for cancer on October 6, 2011, consequently only coaching four games in the 2011–12 season as his doctors modified his schedule during recovery.

The Red Storm received an NIT bid, and earned a victory at the buzzer at Saint Joseph's before falling on the road to Virginia in the next game.

In the 2013–14 season, Lavin led the Red Storm to a 20–13 record finishing conference play in a three-way, third place tie that resulted in another invitation to the NIT, where they were upset by Robert Morris.

In an October 2010 ceremony with Anthony Butler, executive director of St. John's Bread & Life, and Steve Starker of BTIG Brokerage, Lavin made a $35,000, multi-year pledge to aid New York City's homeless and hungry.

Other members of the leadership team are Duke's Mike Krzyzewski, Kentucky's John Calipari, and Michigan State's Tom Izzo.