Gidwitz was born in Chicago and grew up in Highland Park, attending school there before going on for high school to the Hotchkiss School in Lakeville, Conn. He interrupted his undergraduate studies at Brown University in Providence, R.I., to serve as a medic in the Air Force Reserve, but returned to get his bachelor's degree in political science from Brown, where he also studied art. Returning to Chicago after school he worked briefly at what was then Harris Bank before going into real estate with the Burnham Development Co., where he rose to become chairman before leaving for health reasons. His work for nonprofits and governmental agencies included serving as chairman of the board of what was the Illinois Development Finance Authority and on the boards of Mt. Sinai Hospital and the Illinois Chapter of the National Multiple Sclerosis Society. Gidwitz's two marriages ended in divorce. He is also survived by his first wife, Melissa Moe; two daughters, Marjorie Gidwitz-Ferguson and Lauren; stepdaughters Tatjana Belle Dukker and Sara Dukker; a sister, Nancy; and two other brothers, Jim and Tom.