Judge Neil Mullally was born and raised in Muskegon, Michigan. He graduated from Michigan State University in 1968, and for two years was a high school teacher in Traverse City and Muskegon. He then attended the University of Michigan Law School, where he graduated in 1973.

After serving as an assistant Muskegon County Prosecutor, Judge Mullally entered private law practice for thirteen years, and for the past twenty-one years he has served as a judge of the Muskegon County Probate Court, where he is Chief Judge and former Presiding Judge of the Family Court.

Judge Mullally has served in leadership positions in several areas of volunteer service for charitable and arts organizations, including the United Way, Catholic Social Services, the Grand Rapids Diocese Secretariat for Social Justice, the Muskegon Forum Committee, the YMCA, the Muskegon Museum of Art, and the Muskegon County Bar Association. The Michigan Supreme Court appointed him as a member of the Michigan Supreme Court Task Force on Court Reform, and he presently is a member of the Michigan Supreme Court Technology Advisory Group. He also is a board member and past president of the Muskegon Irish American Society and serves as the chairperson of the Grand Rapids Catholic Diocese Review Board that assesses cases alleging abuse of minors by clergy or other church personnel.

In 1998 Judge Mullally introduced the concept of Balanced and Restorative Justice in Muskegon County. The Michigan Department of Human Services has recognized Muskegon County as a leader in establishing Balanced and Restorative Justice in the State of Michigan. In 2007, Judge Mullally was the recipient of the first annual "Neil G. Mullally Restorative Justice Award," an award established by the Westshore Dispute Resolution Center in his name. This award will be presented each year to a person who has supported the practices of balanced and restorative justice in the Muskegon community.

Judge Mullally has presented programs for the Michigan Probate Judges' Association, the Michigan Probate and Juvenile Registers' Association, the Michigan Judicial Institute, the Michigan Foster Care Review Board, and the Michigan Department of Human Services.