Along with Warren Cozzens, he founded Marquette Electronics in 1965 and served as chairman and CEO. The company went public in 1991. After starting with only $15,000 in capital, the company went on to have over $350 million annually in sales. His company put together the nation's first central electrocardiographic system at Northwestern University Medical School. This machine has since become standard in hospitals throughout the United States. The company was also noted for having one of the first on-site day care centers in the nation. In 1982, he and Warren bought the failing Patient MonitoringBusiness Unit from GE and combined it with the existing business. In 1998, he sold Marquette Electronics to GE. The company exists today as part of the Clinical Systems division of GE Healthcare, a subsidiary of the American conglomerate. After stepping aside at his company, Cudahy focused his energies on philanthropy and serving on the boards of other companies. In 1999, according to U.S. Securities and Exchange Commission filings, he invested $10 million in TomoTherapy a Madison, Wisconsin bio-technology start-up. It went public on May 9, 2007, with the stock symbol TOMO. Mr. Cudahy's 10% interest is valued at more than $100 million at present prices. In 2002 he told the story of the founding of Marquette Electronics in the book Joyworks.
Philanthropy
The following institutions have been the recipients of gifts by Michael J. Cudahy:
Michael J. Cudahy Foundation – Foundation through which Cudahy does most of his philanthropy. Not to be confused with the Patrick & Anna M. Cudahy Foundation, set up by his uncle, Michael F. Cudahy.
Pabst Theater – Cudahy bought the beleaguered landmark theatre in downtown Milwaukee, Wisconsin for $1, keeping it open and afloat. He had previously donated over $9 million to the theatre.
Riverside Theater – Cudahy signed a lease to run entertainment programs in the historic Riverside Theater in downtown Milwaukee, Wisconsin.
Pier Wisconsin – Cudahy is spearheading this ambitious project for Milwaukee's lakefront, which some argue would steal the limelight from the nearby Milwaukee Art Museum.