Black comedy doesn’t get any blacker than “Killing Mary Sue” where Dermot Mulroney’s aptly named hot dog of a senator, Bradley Weiner, orders a hit on his stepdaughter Mary Sue.

“This movie was just a fantastic time,” an upbeat Mulroney, 61, enthused. “The whole concept and the whole mashup is really fresh.

“When I read it, I knew that it’s a terrific part for me. Obviously, one that’s kind of a turn on some of the other parts I’ve played — straight politicians or a father in a family drama.

“But killing his stepdaughter? That’s such a turn on its head about so many things. Then seeing Sierra McCormick sink her teeth into Mary Sue Weiner? It’s just too good when you watch it.”

For the cast, including Jake Busey, French Stewart and Martin Kove, “This is a strange mix of having to be real — but obviously the whole thing is preposterous. You have to find a world for that to work and I’ll credit (writer-director-editor) James Sunshine.

“He did it all. He did it even when he was filming in ways that I didn’t understand — until you see how it’s cut together and it plays like a comic book.”

Weiner deserves being ridiculed. But Mulroney knows there have to be layers if it’s going to be laugh-out-loud fun.

“You can’t take it seriously; there’s fun and yet there’s some really true moments. That has to be there.

“The whole movie plays at high pitch. We’re all swinging. It’s obviously not trying to be real, but it’s trying to be real by its own rules.”

Katie Killacky’s Janine Weiner is Mulroney’s wife and Mary Sue’s mother. “She’s a parent who doesn’t know how to communicate with her kids.”

Mulroney’s career really began when at 25 he debuted in a Bruce Willis period picture “Sunset,” followed by a hit, the teen Western “Young Guns.”

In 1997 he scored opposite Julia Roberts in “My Best Friend’s Wedding.” Since 2024 he’s been a regular on NBC’s long-running “Chicago Fire.”

How has he sustained this extraordinary career? “What I know is I set out to do just this. Even as a young actor in my early 20s, I felt it was the assignment to go play as many different types of parts as possible.

“My career hasn’t always been that steady. It managed to look like it because when I wasn’t working, a lot of the times there’s one nice big movie that’s come out. It looks like you’re working sometimes when you’re not.

“These days,” he said, sounding a bit surprised, “people apparently are coming to me.”

“Killing Mary Sue” is available on streaming platforms