NEW YORK – In the last six years, Roger Bart has had quite a ride. “The Producers,” of course. Movies. Television. Remember George, the psychotic pharmacist on “Desperate Housewives”? And now back to Broadway as the lead in Mel Brooks’ stage version of his 1974 film classic, “Young Frankenstein.”

It’s a plum role he initially had doubts about taking.

“I had to think about it,” says Bart, talking about the part of Frederick Frankenstein, the grandson of the man who created the most famous monster of all time.

The actor, his sly smile intact, sits in his spacious dressing room in the nondescript maze of the Hilton Theatre basement and talks about his contribution to the most anticipated musical of the fall season.

Bart has been involved with “Young Frankenstein” since its first readings, during which he first portrayed Frankenstein’s loyal, humpbacked servant Igor (now played by Christopher Fitzgerald).

“Igor I felt fit me like a glove,” he says. “It’s kind of fun to be clown. I’ve always played the clown. The clowns come on, get the biggest, juiciest laughs and then leave.

“Frederick is more often the straight man to all of the kooky characters around him. But the wonderful thing about this particular straight man, like with Leo Bloom in ‘The Producers,’ he does have moments where he can be part of some great clowning gags while also setting up other characters and moving the show along.”

Brooks, who is not shy about voicing an opinion, had no qualms about putting Bart at the head of a large cast of comic actors and musical-theater performers (the list includes Megan Mullally, Andrea Martin, Sutton Foster and Shuler Hensley) who appear in “Young Frankenstein.”

“He’s charming. He’s funny. He’s crazy,” Brooks says of his star. “He has the most thrilling vocal dexterity and winning ways. Who knew he could be another Danny Kaye?”

Well, Susan Stroman, for one. She’s the director and choreographer of both “The Producers” and “Young Frankenstein.”

Stroman had seen Bart in his Tony-winning performance as Snoopy in the 1999 revival of “You’re a Good Man, Charlie Brown.” And then he came to audition for the role of Franz Liebkind, the Nazi musical-comedy writer, in “The Producers.”

“He went out of the room and I went running after him with some sides (dialogue) for the role of Carmen Ghia (the flamboyant ‘common-law’ assistant to director Roger De Bris),” Stroman recalls. “Roger wasn’t prepared for it, but he read and got the job.”

“The Producers” became the stuff of legend on Broadway. Rhapsodic reviews. A record 12 Tony Awards (Bart got a nomination but didn’t win). The actor kept coming back to the production during its six-year run, first as Carmen Ghia and then as one of the replacements for Leo Bloom, the nebbish accountant first played by Matthew Broderick.

“It was a great show to play because it kept my chops good,” Bart says. “There’s nothing more instructive than the immediate response of an audience. Each time I came back to the show, the part became more my own and less of what I learned from being with Matthew for first year and a half.

“Plus it always was a great opportunity as I went across the globe to do movies and TV over the last few years, ‘The Producers’ always guaranteed me three or four months of being with my daughters. That was important to me.” Bart has two children: Alexandra, a senior at the University of Pennsylvania, and 6-year-old Eller, named after her great-grandmother.

“Life changed at 40 for me, as predicted by my acting teacher when I was leaving college,” Bart says. “I became more hirable and more interesting. … I’m not sure why.

“I’ve always looked like I was a kid. I’m 45 now and I look like I’m 45. I think I lost the last traces of my youth, which I think helped me.”

Helped him, Bart says, in terms of more work in movies and television. “There are just more roles for quirky people who are my age,” he says. “I found that because of ‘Desperate Housewives’ and these movies that I was doing as well as the time and experience I had with ‘The Producers.'”

The films include a small but choice scene in the current hit “American Gangster” and a rather cutting part in last summer’s slasher-horror flick “Hostel: Part II.” But “Young Frankenstein” dwarfs them all in terms of satisfaction.

While he dithered about taking the role, friends told him, “What! Are you crazy? There is nothing to think about. You are ready for these challenges.”

“I should have known,” Bart says. “These are people (Stroman and Brooks) I have worked with for years. There’s a comfort level. It’s like family.”

Stroman says she always wanted Bart to play the Ivy League-educated Frederick Frankenstein, a man with his own set of peculiarities.

“Roger is a leading man but he is also a character actor – he can straddle both sides,” the director says. “Dr. Frankenstein needs to carry the show, but he also has to have that crazy, mad-scientist side.”

As Brooks, who wrote the show’s score and co-authored its book, puts it: “He always sticks to the character – and within it, he’s dazzling.”

Stroman, who first made a name for herself as the choreographer of such shows as “Crazy for You” and the 1994 revival of “Show Boat,” also praises Bart’s physicality.

“He’s a very good dancer and has a fearless quality about him, which I love. He’s up for trying anything. His movement is very much in character. He moves like you think an upper-class Yale graduate would move. He also understands the time period of the 1930s (which is when ‘Young Frankenstein’ is set).”

Bart tries not to think – or read about – about the hype that has followed “Young Frankenstein” to Broadway after its summer tryout in Seattle.

“Susan and I work as hard as we can,” he says. “We’re pretty rational about it. We just want to put on a great show and make it the best it can possibly be.”