Sean McDonnell completed his 10th season as head coach at Case Western Reserve in 2012-13. McDonnell was named just the third men's basketball coach in program history in 2003. 

Since his arrival, McDonnell has recruited, developed and coached numerous players who were awarded All-University Athletic Association (UAA) recognition. Among these honorees was Case Western Reserve's all-time leader in both scoring and rebounding, Carson Oren '06.  Oren was a finalist for the 2006 Jostens Award, presented annually to the NCAA Division III Player of the Year. Furthermore, many of McDonnell's players have earned All-UAA and all-district academic honors. Most recently, 2013 graduate Austin Fowler was named to the Capital One Academic All-America® Team, marking the third time in four seasons that a Spartan received the honor.

Prior to taking the reigns at Case Western Reserve, McDonnell served as the men's basketball coach for three seasons at Hiram College in Hiram, Ohio. As a member of the North Coast Athletic Conference (NCAC), McDonnell coached Hiram to two post-season appearances and developed two second-team All-NCAC performers. Hired at the age of 25, McDonnell was the youngest NCAA men's basketball coach in America in 2001.

From 1996-2000, McDonnell served as the assistant men's basketball coach at Williams College in Williamstown, Massachusetts and at Le Moyne College in Syracuse, New York.  As an undergraduate at Boston College, McDonnell was a student assistant coach where he contributed to the development of six future NBA players. As an assistant, McDonnell was mentored by two coaches who earned National Coach of the Year honors by the National Association of Basketball Coaches (NABC).

Between 1995-2005, McDonnell directed a number of developmental summer basketball clinics in Greece, South Africa, the Republic of Macedonia and the Czech Republic. These experiences abroad motivated McDonnell to organize summer trips to Brazil in both 2007 and 2010 for his Spartan teams. Additionally, McDonnell led the Central Region's men's basketball team in New York's Empire State Games from 1998-2000.

McDonnell earned a Master of Science degree in education from Le Moyne in 2003 and a Bachelor of Arts degree in English from Boston College in 1996. McDonnell is a member of the NABC Division III All-America Committee and chairs the Nomination Committee for the NABC Division III All-Star Game in Salem, Virginia. He previously served on the Great Lakes Regional Advisory Committee for the Division III NCAA Tournament. 

McDonnell resides in Cleveland Heights with his wife, Angie, and their children, Leah and Conor.