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- Bernie Mac, actor, stand-up comedian, The Bernie Mac Show, Madagascar: Escape 2 Africa, Ocean's Eleven and its sequels
- Justina Machado, actress, Six Feet Under, Missing, Three Rivers
- Pete Mackanin, bench coach for the Philadelphia Phillies
- Fred MacMurray, actor, My Three Sons, Double Indemnity, The Apartment
- Earle S. MacPherson, automotive engineer that developed the MacPherson strut
- Amy Madigan, actress, Carnivàle
- Slip Madigan, college football player and coach of football, basketball, and baseball
- Michael Madsen, actor, Die Another Day
- Virginia Madsen, actress, sister of Michael Madsen
- Corey Maggette, player for the Charlotte Bobcats
- Ron Mahay, relief pitcher for the Minnesota Twins
- John Mahoney, actor, Marty Crane on Frasier
- Terrence Malick, filmmaker
- John Malkovich actor, producer and director Con Air, In the Line of Fire
- David Mamet, screenwriter, playwright, director, producer, The Unit
- Harry Manfredini, film composer
- James Robert Mann, politician (Republican), attorney, Chicago City Alderman, U.S. Congressman
- Michael Mann, film director
- Joe Mantegna, actor, voice actor, Criminal Minds, Joan of Arcadia, The Simpsons
- Joe Mantello, actor
- Ray Manzarek, co-founder and keyboardist for The Doors
- Shawn Marion, forward for the Dallas Mavericks
- Richard Martini, writer, director
- Russell Maryland, NFL defensive tackle and College Football Hall of Fame inductee
- Edgar Lee Masters, author and poet
- Mary Elizabeth Mastrantonio, actress, The Color of Money
- Marlee Matlin, Academy Award-winning actress, Children of a Lesser God
- Jason Maxiell, player for the Detroit Pistons
- George S. May, businessman, golf promoter
- Curtis Mayfield, soul, R&B, and funk singer, songwriter, and record producer
- Chi McBride, actor, The John Larroquette Show, Boston Public, Human Target
- Mercedes McCambridge, Academy Award-winning actress
- Jenny McCarthy, model, actress, author, activist
- Melissa McCarthy, actress, Mike & Molly, Gilmore Girls, Samantha Who?
- Mike McCormack, Hall of Fame NFL offensive tackle, head coach, president and general manager
- Cyrus Hall McCormick, businessman and inventor of the McCormick Reaper
- Robert R. McCormick, newspaper publisher and philanthropist
- LisaRaye McCoy-Misick, actress, All of Us, Single Ladies
- Elizabeth McGovern, actress
- Tim McIlrath, musician, Rise Against
- Sherrick McManis, cornerback for the Houston Texans
- Donovan McNabb, quarterback for the Washington Redskins
- John McNaughton, film and television director
- Marcus McNeill, offensive tackle for the San Diego Chargers
- Ryan McPartlin, actor, Chuck, Living With Fran
- Joseph Medill, newspaper owner and publisher, Mayor of Chicago
- Chris Medina, singer-songwriter and former American Idol constestant
- Rashard Mendenhall, running back for the Pittsburgh Steelers
- Alex Meneses, actress, model, Dr. Quinn, Medicine Woman
- Charles Edward Merriam, political scientist, professor
- Laurie Metcalf, actress, Roseanne
- Robert H. Michel, (born 1923), politician (Republican), longtime member of Congress and former House Minority Leader
- Ludwig Mies van der Rohe (1886–1969), modernist architect
- Bob Miner, co-founder of Oracle Corporation
- Bob Mionske, attorney and former Olympic and professional bicycle racer
- John Francis Mitchell, electronics engineer and President & COO of Motorola from 1980-1995
- Nazr Mohammed, center for the Oklahoma City Thunder
- Harriet Monroe, poet
- Meredith Monroe, actress, Dawson's Creek, Criminal Minds
- Eric Monte, screenwriter
- Dwight L. Moody, evangelical minister and publisher
- William Vaughn Moody, dramatist and poet
- Christina Moore, actress, Hawthorne, Hyperion Bay, Hot Properties
- Stephen Moore, economic writer, policy analyst, founder of the Club for Growth
- Read Morgan, actor
- Jennifer Morrison, actress, model, House, How I Met Your Mother, Star Trek
- Mark Moses, actor, Desperate Housewives, Grand, Mad Men
- Senta Moses, actress, General Hospital, Running the Halls, Home Alone
- Markos Moulitsas, founder of the liberal blog Daily Kos, columnist for Newsweek and The Hill
- George Mundelein, Roman Catholic Bishop of Brooklyn and Cardinal Archbishop of Chicago
- David Lee Murphy, country music artist
- Bill Murray, actor, comedian, the Ghostbusters movies, Charlie's Angels, Tootsie
- Brian Doyle-Murray, comedian, actor, voice artist, Saturday Night Live, The Marvelous Misadventures of Flapjack, The Middle
- Joel Murray, actor, Dharma & Greg, Love & War, Grand
- James Murtaugh, actor
- John Musker, animation director, Aladdin, Hercules, The Princess and the Frog
- George Musso, Hall of Fame offensive lineman for the Chicago Bears
Read more about this topic: List Of People From Illinois