Mani Grewal was born and raised in Modesto. After attending Modesto Junior College, he obtained an Associate Degree in Accounting and a Bachelor of Science degree in Business Administration. He also completed the Management Program at the University of Pacific Eberhardt School of Business. He and his wife, Jas, are raising their four children in Modesto.
Mani Grewal has been a member of the Modesto City Council since 2015. He has served as a member of the Modesto Planning Commission, Stanislaus Council of Governments Policy Board, California State University of Stanislaus Foundation Board, the Stanislaus County Interfaith Council, and the Memorial Hospital Foundation.
Governor Newsom appointed Mani Grewal to Supervisor for the 4th District of the Stanislaus County Board of Supervisors on November 21, 2020.