In 12 seasons at CUA, Lonergan guided the Cardinals to nine NCAA Tournaments, and an overall record of 251-88, a school-best.740 winning percentage. The Cardinals won seven straight regular-season conference championships. No other college coach in the nation during that time – at any NCAA division – accomplished that feat. Lonergan was recognized for the achievement during the 2004 NCAA Division I Final Four. The team won the 2001 Division III National Championship during that run. After spending the 2004-05 season as an assistant at University of Maryland, College Park under Gary Williams, where he helped the Terrapins to the NIT Semifinals, Lonergan accepted the head coaching position at the University of Vermont, replacing Tom Brennan. Lonergan coached the Catamounts for six seasons where he averaged 21 wins a year and finished with a career record of 126-68 and.649 winning percentage at UVM, which is the second highest in school history among coaches with at least 100 career decisions, behind current UVM coach John Becker. In the last six seasons he guided Vermont to four postseason appearances, including a trip to the NCAA Tournament in 2010. He ranks third all-time at UVM in career wins. In May 2011, Lonergan was hired by George Washington University Athletic Director and former America East Commissioner Patrick Nero to take over as head coach of the Colonials. Early in his tenure, Lonergan highlighted his origins in the Washington, DC metropolitan area and his understanding of Colonials basketball's historical reliance on foreign-born recruits and committed to recruiting locally, nationally and internationally. His first complete recruiting class boasted two players from the DC area and players from Argentina, Greece and Denmark. The Colonials struggled to consecutive losing records under Lonergan in 2011-12 and 2012–13, marking the first time in his Division I coaching career that a Lonergan-coached team failed to reach the postseason in consecutive seasons. In 2013-14, GW finished the year 24-9, finishing third in the Atlantic 10 and earning a ninth-seed in the NCAA Tournament, where the Colonials lost to Memphis. Following the trip to the NCAAs, George Washington announced that Lonergan had signed a contract extension that keeps him at GW through the 2020-21 season. Mike Lonergan completed his fourth season as head coach for men's basketball at George Washington University in 2014-15, leading the Colonials to back-to-back 20-win seasons and postseason appearances for the first time since 2006 and 2007. He guided GW to 22 victories, seventh-most in a season in program history, and a return trip to the postseason with an at-large selection to the National Invitation Tournament. Coach Lonergan helped the Colonials post a 60-54 opening round victory at Pittsburgh for the program's first-ever win in five NIT appearances. Lonergan led the Colonials to a 5-0 record to open the 2015-16 season, including a noteworthy upset victory over the No. 6 Virginia Cavaliers on November 16, 2015. This was George Washington's first win over an opponent ranked that high since beating No. 1 Massachusetts 78-75 on Feb. 5, 1995. The Colonials would go on to finish the regular season with a 23-10 record, good enough for an NIT invite for a second consecutive season. They would go on to win the NIT Championship Game that season. In a July 21, 2016 article in the Washington Post, several former players charged Lonergan with "verbal and emotional abuse", charges that Lonergan did not respond to in a statement. The article also noted that three players transferred out of the university after each of the previous four seasons. Later that day, George Washington University announced that it was hiring outside counsel to assist in the investigation of these allegations. Lonergan was fired on September 16, 2016, reportedly on the basis of the allegations. Nearly a year later on September 13, 2017, Lonergan and George Washington officials settled the former coach's legal dispute against the school over his firing. Both sides continue to maintain their initial positions, but per the agreement the settlement cannot be publicly discussed. On the May 10, 2017 edition of Randy Foye's Outside Shot podcast, guest Jeremy Lin described an incident which alleged that a Vermont coach called Lin, an Asian-American, a racial slur while Lin was playing for Harvard in a game at Vermont in 2006. Lonergan refuted the allegation. On November 18, 2018, Deadspin published a story which detailed the conduct and dismissals of both former George Washington athletic director Patrick Nero and Lonergan along with the tumultuous relationship between the two.
Personal life
Lonergan and his wife Maggie have five children: John, Margaret, Michael Jr., Robert and Regina. Mike and Maggie met while both working at the basketball camp of legendary DeMatha Catholic High School coach Morgan Wootten. Lonergan has been involved with the Coaches vs. Cancer campaign from the beginning to help raise awareness about the devastating disease which took his mother's life.