Senator Mulroe was born and raised in Chicago. He and his wife Margaret and their four children reside in the Edison Park neighborhood. John has a law practice, while his wife works at a neighborhood school as an administrative assistant.
In addition to his law background, Senator Mulroe has worked in public service as an assistant state's attorney for Cook County, a hearing officer with the Chicago Park District and an arbitrator with the Cook County Mandatory Program. His professional background includes working as a CPA and as an adjunct instructor at William Rainey Harper College.
Senator Mulroe earned his bachelors degree in accounting from Loyola University of Chicago and earned his CPA, and also earned his law degree from Loyola University of Law. He is a member of the Chicago Bar Association and Illinois State Bar Association. He has been active in civic organizations including the St. Juliana School Board, Edison Park Community Council, Edison Park Chamber of Commerce, Edison Park Youth, Niles Park District and St Angela Education Foundation.