O'Brien (born April 9, 1950) is an American college basketball coach who has served as coach of St.
Bonaventure University (1982–1986), Boston College (1986–1997), Ohio State University (1997–2004) and Emerson College, a Division III school in Boston (2011–2014).
O'Brien was hired as head coach on April 7, 1997 after Ohio State had fired previous coach Randy Ayers.
O'Brien guided the Buckeye program to the 1999 Final Four, 2000 and 2002 Big Ten regular-season co-championships, the 2002 Big Ten Tournament Championship, four 20-win seasons and a school record four-consecutive NCAA tournament appearances (1999–2002).
Ohio State later had to vacate all wins from 1999 to 2002, remove all references to team accomplishments for those years, and pay back all tournament money due to rules violations during O'Brien's tenure.
On June 8, 2004, then-Ohio State athletic director Andy Geiger fired O'Brien for alleged NCAA rules violations.
The Ohio Court of Claims determined that Ohio State breached its contract with O'Brien by terminating him and awarded him $2.4 million.
However, O'Brien was given an NCAA "show-cause" order effectively banning him from coaching from 2006 to 2008, and only returned to coaching in 2011.