Michael J. Day became a member of East Bay Automotive Machinists Local Lodge 1546 in Oakland, California in 1964. He began steadily working up through the ranks of District Lodge 190 and in 1974, he was elected Business representative. In February 1989, he became the District's Directing Business representative.

Day amassed a distinguished history of involvement in the labor movement and in the pursuit of better wages and working conditions for the men and women of the IAM.

His achivements include the vice presidency of the California State Federation of Labor, AFL-CIO (a post he had still held); membership on the IAM's Law Committee (he was reelected this year), past-presidency and current Executive Board membership on the California Conference of Machinists; chairmanship of the Automotive Industries Pension Fund; chairmanship of the Automotive Industries Health & Welfare Trust Fund; presidency of East Bay Automotive Council; presidency of the Northern California Automotive Coordinating Committee; chairmanship for the Union on the Western States Truck-Line negotiating Committee for the Western Territory.

Instrumental in organizing District Lodge 190's Annual Golf Tournament benefitting Guide Dogs of America, Day served on the GDA's Board of Directors.