Michael Edward Hannigan, of Mequon, WI, passed away on May 19, 2026, surrounded by his loving family. He was 68.

Born July 7, 1957, in Chicago, Illinois, Mike was the son of the late John “Jack” Hannigan and Carol Hannigan (Anderson). He graduated from St. Rita of Cascia High School Chicago before earning his engineering degree from the University of Illinois Champaign-Urbana, going on to secure his professional engineering license and an MBA from DePaul University. Mike went on to build a successful 40-year career at Johnson Controls. He was deeply humble and selfless, far more interested in hearing about the passions, interests, and lives of the people around him than speaking about himself. 

Mike's greatest joy was his family. A devoted husband, father, and grandfather. He showed up without exception and never missed a game, match, or moment that mattered to his children, traveling wherever he needed to be and cheering them on every step of the way.

Mike was a lifelong Chicago sports fan who remained fiercely loyal to the Bears, White Sox, and Illini no matter how heartbreaking the season.  He especially enjoyed handicapping and betting the horses. His family loved that Mike could never resist betting on a horse if its name reminded him of a loved one.  

For the past 15 years, Mike faced cancer with remarkable resilience, strength, and unwavering optimism. Through every challenge he maintained the same steady demeanor and sense of humor that defined him throughout his life. He never lost his ability to make light of difficult moments, and his family will forever miss the silly jokes that often made him laugh more than anyone else in the room.

Mike is survived by his beloved wife of 36 years, Molly; his three children and their spouses, John (Maureen), Kevin (Jenny), and Maggie (Dan); his two grandchildren; and his brothers Andy (late Linda), John (Bridgette), and Bob (Denise).

A private service will be held by the family. In lieu of flowers, the family kindly asks that donations be made in Mike's memory to https://audaxity.donordrive.com/teams/5201/donate, supporting the oncology team at Froedtert Medical College of Wisconsin whose care and dedication meant so much to him and his family over the past 15 years.