Stephen Baldwin's first thought when his agent told him about The Young Riders was what you'd expect from a self-described tough nut from Massapequa, Long Island: There's no way I'm playing some network cowboy weenie." Of course, Buffalo Bill Cody -- even the teen-dream version in the ABC Western -- isn't exactly a weenie, and by now The Young Riders is no longer a tenderfoot (it concludes its second season with a two-hour episode). At least, it has brought the 24-year-old to Tucson, where the show is filmed, and to the sprawling , two-bedroom, southwestern-style house he shares with his wife of 10 months, Kennya, 24, a graphics designer.

As he sits in the quiet of his rock garden, this revels in a lifestyle that's a far cry from the headline-rich high jinks of his eldest brother, Alec. Not that Stephen disapproves. In fact, he gasps in admiration when shown a Cosmopolitan photo of Alec's girlfriend and Marrying Man co-star, Kim Basinger. "Wow," says Stephen, who has met the actress. "No wonder my brother wants to go out with her."

No, Stephen's relatively low profile -- but a distinctive one. He is the youngest, leanest and blondest of the acting brothers: Alec, 33, who these days needs no introduction; 28-year-old Billy (Internal Affairs, Backdraft), who very soon won't need one; and 30-year-old Danny (CBS's Sydney) who still does. (There are also two non-acting sisters: Elizabeth, 35, mother of six and head of Stephen's fan club, and Jane, 26, a physical therapist.) Alec, notes, Danny, is the clan's "best-trained actor, and I think Stephen and I are just walk-on-and-do-it, natural actors." And Stephen who admits he's "kind of goofy," may be the most quirkily appealing. "But I don't think I'm ugly," he notes. "I've gone from a goofy Howdy Doody to a little bit more masculine Howdy Doody."

Howdy would have a needed a how-itzer to survive growing up in the rambunctious, middle class family, which was presided over by dad Alexander, a high school history teacher and football coach, and mom Carol. The precarious situation of being the littlest maybe turned Stephen into a cutup. "I did Paul Lynde impersonations," he says.

Alec himself used to do a mean Sammy Davis Jr., but he's also had a serious, academic-oriented side. (Carol, 61, still isn't quite accustomed to Alec's stardom. "I thought he and Billy would go to law school," she says.) Stephen, on the other hand, was never "the pen-and-paper type." His great passion at Massapequa High School was singing choral music and Italian opera, and he was a three-time all-state soloist. Unlike his brothers, who attended college, Stephen dropped the solo act and went straight for acting. "That was what I was looking for," he says, and once Alec went that route, "we all kind of fell into it."

But Baldwins don't really just "fall" into anything -- they share a drive and a competitiveness instilled, says Danny, by their dad, who died of lunch cancer in 1983. "I always remember a look that he used to give me," says Stephen. "It was saying, 'You're a bit of a jerk because of your stubbornness and ignorance, but at the same time, I know you have it. I know you have talent.' It was an interesting glare."

Protracted gazing has served well: An agent spotted him some five years ago, when he was working in a Manhattan pizza parlor. So began a career that has included parts in Born On the Fourth Of July, Last Exit To Brooklyn and China Beach, as well as a Calvin Klein ad. And it was a long, longing look that brought him together with Brazilian-born Kennya when he noticed her across the aisle on a Manhattan bus in the winter of 1987. "She went five stops past her stop because she knew I was looking at her," he says/ "When we got off the bus, she gave me her number and a kiss on the cheek and -- I'm serious -- my heart was the size of a softball."

Serious is an adjective that rarely crops up when fellow riders discuss. "When the sun is going down," says director Virgil Vogel, "he's still having fun, and we're still trying to get the shot."

For a while, was having way too much fun, "getting drunk with the boys on weekends and being an ass," he confesses. Then, one morning two years ago, "I woke up, said 'This isn't me,' and took steps to be sober."

In these less rowdy times, shoots pool at clicks, a local billiard parlor and cruises around on his prized Fat Boy Harley-Davidson. And he hopes someday he can pal around with another bunch of guys -- sons. "I want an army of them," he says. "Yeah, I love little kids. 'Cause I'm a little kid."

Picture is a still from the episode Survivors