Michael Emmet Walsh (born March 22, 1935) is an American character actor who has appeared in over 100 film and television productions.

Walsh was born in Ogdensburg, New York, the son of Agnes Kathrine (née Sullivan) and Harry Maurice Walsh, Sr., a customs agent. He first came to prominence in the 1978 crime drama, "Straight Time," in which he played a sadistic parole officer. One of his most acclaimed roles was as Bryant in Ridley Scott's cult classic Blade Runner. Another notable role is as the double crossing private detective in Blood Simple (1984) for which he won the 1986 Independent Spirit Award for Best Male Lead. Walsh made occasional guest appearances on Home Improvement as Tim Allen's father-in-law. In Christmas with the Kranks, he played one of Allen's neighbors. He also appeared as Alex, a motorcycle cop who appointed himself as Sandy Stockton's (Sandy Duncan) chaperone/ protector on The Sandy Duncan Show in 1972.

According to Roger Ebert's "Stanton-Walsh Rule" - "no movie featuring either Harry Dean Stanton or M. Emmet Walsh in a supporting role can be altogether bad". Ebert later conceded that this rule was broken by 1999's Wild Wild West.

Wonderfully talented, heavyset character actor (from New York, but regularly playing Southerners) M. Emmet Walsh has made a solid career of playing corrupt cops, deadly crooks, and zany comedic roles since the early 1970s. First appeared in a few fairly forgettable roles both on TV and onscreen before cropping up in several well remembered films, including a courtroom police officer in What's Up, Doc? (1972), as the weird Dickie Dunn in Slap Shot (1977), and as a loony sniper hunting Steve Martin (I) in Jerk, The (1979). On-screen demand heated up for him in the early 1980s with attention-grabbing work in key hits, including Brubaker (1980), Reds (1981), and as Harrison Ford (I)'s police chief in the futuristic thriller Blade Runner (1982). Walsh then turned in a stellar performance as the sleazy, double-crossing private detective in the Joel Cohen (I) and Ethan Coen film noir Blood Simple. (1984), and showed up again for the Coens as a loud-mouthed sheet-metal worker bugging Nicolas Cage in the hilarious Raising Arizona (1987). As Walsh moved into his fifties and beyond, Hollywood continued to offer him plenty of work, and he has appeared in over 50 movies since passing the half-century mark. His consistent ability to turn out highly entertaining portrayals led film critic Roger Ebert to coin the "Stanton-Walsh Rule," which states that any film starring Walsh or Harry Dean Stanton has to have some merit. And the "M" stands for Michael!