James Tupper laughs heartily when he hears people speculating that he must be a couple of years out of acting school, that he’s a new kid on the Hollywood scene because no one had ever heard of him before he landed a regular role on the ABC comedy “Men in Trees” back in 2006.

He thinks it’s funny because, well, there’s this strange thing about being an overnight success: It almost never happens overnight. In this case, the instant fame came about 15 years into a career that was relatively undistinguished for the majority of that time.

“I did a lot of plays, including ‘After the Rain’ off-Broadway in New York,” Tupper, 43, explained. “I took a lot of audition technique classes to fill up the time when I wasn’t working, just to stay active. And I wasn’t working a lot. People would think, ‘Oh, what a talented guy, it’s such a shame.’ But you know, I didn’t see it that way at all. Paying your dues is just part of the deal.”

In this case, that meant plenty of small roles in plays and what he estimates to have been 30 TV commercials “to pay the rent and allow me to do theater at night where I made nothing.” One of those ads was for Volvo and involved his sitting in a car kissing a woman, only to have a piano fall on the car.

“Sometimes,” Tupper interjected philosophically, “you have to wait a little time before your ship comes in.”

But come in it has. The first evidence was the role in “Men in Trees,” which starred his now-steady girlfriend Anne Heche. There was also a four-episode arc as Christina Applegate’s suitor on “Samantha Who?” and a role in the feature “Me and Orson Welles” opposite Zac Efron, Claire Danes and Ben Chaplin. It will open in theaters in September, about the same time as the medical drama “Mercy,” Tupper’s second series as a regular, will premiere on NBC.

But before this fall’s two-pronged Tupper splash rolls out, he has a summertime project designed to tide over the ruggedly handsome, bearded actor’s growing legion of fans. It’s the Hallmark Channel Original Movie “The Gambler, the Girl and the Gunslinger,” a lighthearted western that will premiere at 9 p. m. Saturday.

Tupper represents the “Gunslinger” in the title. To be sure, the idea of the soft-spoken heartbreaker decked out in a macho cowboy getup may well be too much for the ladies to bear. After all, this is a dude who recently made the “Sexiest” lists of TV Guide and US Weekly. He also gets to match wits with a fellow by name of Dean Cain. (He’s the “Gambler”).

“I just had the greatest time doing the Hallmark movie,” Tupper said. “Dean is the greatest guy. We hung together the whole time of the shoot, which was actually only like 15 days. Dean is exactly as he seems, just a top-notch man. It was a little like meeting Superman. But then he’s just so down to earth you forget that.”

Working on “The Gambler, the Girl and the Gunslinger” helped make Tupper feel like a real cowboy — sometimes. Other times, it was more about faking it effectively.

“There was this one scene we did where I’m flying through a gate on my horse,” Tupper said. “The bandits are shooting at us. And unfortunately, my horse didn’t know the shooting was going to happen. So he kind of freaked and put on the breaks. But he stopped right near where the trainer had put his mark. If you looked behind us, you saw these four skid marks where his hooves dug in. He knew what he was doing way more than me.”

It was also special for Tupper to go horse riding with Homer, Heche’s 7-year-old son from her marriage to Coley Laffoon. This past spring, in March, Tupper became a father for the first time when Heche gave birth to son Atlas, whom they call “Attie.”

The kid is clearly the apple of daddy’s eye. “He’s a sugarplum, just a sweetheart,” Tupper said. “He doesn’t cry at all. He’s really mellow. But I’ve also learned that having a baby is a little bit like having an unreasonable employer around the house. He doesn’t give breaks, ever! And it’s like you’re working for him all the time.”

Tupper emphasizes that he and Heche are “seriously committed” to each other but have no plans to marry in the near future.

“We’ve both experienced that before, without success, so our plan is just to stay engaged forever,” Tupper said. “I’m buying her a new ring every year to re-establish our commitment, which means I’m really doing my part to stimulate the economy. I also just bought Anne an upright piano. Not that that has anything to do with being engaged forever.”

Relationship aside, Tupper is excited about the prospects for “Mercy,” an hour that follows the lives and careers of a hospital staff as seen through the eyes of its nurses. He gets to play a doctor who also happens to be the other man in a love triangle involving a married nurse (Taylor Schilling). The series also stars Michelle Trachtenberg and veteran Delroy Lindo.

The word that best describes the direction his life and career are going in these days is “lucky,” Tupper says.

“Yeah, I paid some dues and all of that by doing guest roles in episodics like ‘How I Met Your Mother’ and ‘CSI: New York,’ ” he said, “but the truth is I’m tremendously lucky. I know that luck is the hallmark of hard work. But hard work alone isn’t enough. So I’ll take lucky for the moment.”