Madsen was found unresponsive in his home in Malibu, California, on Thursday morning and pronounced dead, Los Angeles County Sheriff's Department Watch Commander Christopher Jauregui said.
He is believed to have died of natural causes and authorities do not suspect any foul play was involved. Madsen's manager Ron Smith said cardiac arrest was the apparent cause.
Madsen's career spanned more than 300 credits stretching back to the early 1980s, many in low-budget films. But his most memorable screen moment may have been the sadistic torture of a captured police officer — while dancing to Stealers Wheel's Stuck in the Middle with You — as Mr Blonde in 1992's Reservoir Dogs.
He would become a Tarantino regular, appearing in the Kill Bill films and The Hateful Eight.
"In the last two years Michael Madsen has been doing some incredible work with independent film including upcoming feature films Resurrection Road, Concessions and Cookbook for Southern Housewives, and was really looking forward to this next chapter in his life," his managers Smith and Susan Ferris and publicist Liz Rodriguez said in a statement.
They added that he "was one of Hollywood's most iconic actors, who will be missed by many".
During a handprint ceremony at the TCL Chinese Theatre in November 2020, Madsen reflected on his first visit to Hollywood in the early 1980s.
"I got out and I walked around and I looked and I wondered if there were someday, some way that that was going to be a part of me. And I didn't know because I didn't know what I was going to do at that point with myself," he said.
"I could have been a bricklayer. I could have been an architect. I could have been a garbage man. I could have been nothing. But I got lucky. I got lucky as an actor."
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