Art doesn't imitate life anymore for Mark Wahlberg. Vincent Chase and his boys on Entourage (loosely based on executive producer Wahlberg’s swingin’ single days) still stumble to the links with last night’s whiskey shots wafting from their pores, oblivious to any scheduled tee time. Not Wahlberg. On this sunny afternoon, the veteran actor and his real-life crew—trainer Brian Nguyen, Eiran Zell, and Rob Baldwin—are right on time at the first tee at the Moorpark Country Club, 45 miles northwest of his Beverly Hills home. Wahlberg, now 40 and a long-ball (he regularly plays from the back tees) nine-handicap, mixes the requisite trash talk and bullshitting with stories about his kids, a reminder that his favorite diversion rarely allows for an impromptu 36 holes or a couple of beers at the 19th hole. “Most days I’m up at five-thirty, on the course by six, and off the course by eight helping my wife with the kids,” he says. “I’m only out there now once or twice a week.” What a contrast from the Wahlberg we first got to know. Nearly two decades ago, he strutted onto the public stage as a 20-year-old pants-dropping, underwear-modeling rap artist. Few (if anyone!) envisioned that today he’d not only be a respected Academy Award–nominated actor, but also a dedicated family man (he married his longtime girlfriend, Rhea Durham), father of four–and as much of a “player” in Hollywood as he is on the golf course. Wahlberg executive-produces three HBO series, including the hit Entourage, which is in its eighth season. Yet films remain his primary focus. Last year, he appeared in a rare comedic role in The Other Guys, in which he and Will Ferrell played a pair of bumbling NYPD detectives. Previous notable roles (The Departed, Boogie Nights, I Heart Huckabees) have showcased his comic timing, but Guys gave him the opportunity to get a little goofy, a challenge Wahlberg approached with the same intensity as he did portraying his more intense characters. “They’re all the same,” he says. “I try to become the character and play it as real as possible. No matter how absurd it is, I need to believe in it 110%.”

Wahlberg applies the same rigid dedication to his body, though his initial efforts—like those of a young, inexperienced actor—were fairly short-sighted. “When I first started training, I was trying to lift the gym,” Wahlberg recalls. “As much weight as possible, all day, every day.” Working with Nguyen, a former trainer for the Jacksonville Jaguars, on the set of the 2006 football flick Invincible, Wahlberg changed his strategy dramatically. He played Vince Papale, a true-life regular guy who earned a spot on the Philadelphia Eagles, and played with them for three seasons (1976–1978). Not surprisingly, Wahlberg trained and practiced like a real NFL player. “With all the hits I was taking on that movie, Nguyen was still able to get me ready for the next day and back on the field after 12 hours of shooting and hitting.” When the film wrapped, Wahlberg hired Nguyen to work with him full time to prep for a series of physically demanding films he had in the pipeline, including Max Payne and Shooter. “[Mark’s] philosophy is ‘If you’re not gonna show me, blow me,’ ” Nguyen says. “We started incorporating more of the functional training we do today.”

The duo’s training kicked up a notch in early 2007 when Wahlberg signed on to play boxer “Irish” Micky Ward in The Fighter. The biopic was a passion project for Wahlberg, who shares Ward’s Massachusetts upbringing and Irish-American heritage. It took over three years to complete because of casting and directorial changes, but Wahlberg stayed in shape for the duration. He and Nguyen often began workouts at 4 a.m. in the warehouse-size home gym on his Beverly Hills estate in order to get in two hours of training before a 12-hour shoot. “I trained while I was making other films,” Wahlberg says. “The great thing [about the long delays on Fighter] is it gave me more time to look like a real fighter, which was always my goal anyway.” That’s why much of Wahlberg’s training now takes place in the ring. “Boxing was always an element of our workouts,” Nguyen adds. “Whether it’s jumping rope or sprints up and down the court, we do it in three-minute rounds followed by sparring at the end of every workout.”