Mark Wahlberg's Career, Fatherhood

Showing his softer side is not something Mark Wahlberg is really known for. The star once brandished an attitude as hard as his body.

He went from prison to pop stardom, and then made a name for himself as an actor in his 20s, playing mostly tough-guy roles. Wahlberg menaced Reese Witherspoon in the 1996 movie Fear, but is now more likely to swing a golf club than a punch.

To prepare for his role as an introspective fireman in the upcoming movie I Heart Huckabees, he went to therapy. His influence is also found behind the camera, as producer of the HBO series Entourage — all signs of how he's reinvented himself time and time again.

"I can't understand sometimes why I've been given so many chances," Wahlberg told 20/20. "So many friends and so many other kids … haven't been given any chances."

Finding a Future From Prison

As the youngest of nine children born to a working-class family in Boston's Dorchester neighborhood, Wahlberg was driven to just survive. Yet that drive made him all too eager to run with the toughest in town, and he was abusing drugs and breaking laws before he needed to shave.

"I would do something stupid, to get the money to get the drugs and the alcohol. And then, I would do something even more stupid, you know, once I was high and drunk," said Wahlberg.

While using drugs and allegedly spouting ethnic slurs, a 16-year-old Wahlberg robbed and assaulted two Asian men. He served 45 days behind bars.

"Waking up finally being sober, realizing how many people I'd hurt, both physically and emotionally, my family, innocent people … I knew that I had to make a change in my life, and I was determined to do that," he said.

'Good Vibrations'

Wahlberg emerged from prison with an improved attitude and an industrial-strength physique. Meanwhile, his brother Donnie had found fame and fortune in the boy band New Kids on the Block.

Donnie wrote an album's worth of songs for his kid brother, and two years after his prison term ended Mark Wahlberg had become the leader of Marky Mark & the Funky Bunch. Their CD went platinum with the hit "Good Vibrations," and their stage act featured a shirtless Wahlberg dropping his pants.

Designer Calvin Klein made him the spokesmodel for his new men's underwear advertising campaign, and it worked. The buff star was a hit with both straight women and gay men in a shared campaign with supermodel Kate Moss.

"It really hit me, when I went to San Francisco with Calvin Klein, and it was probably 20,000 guys out there," said Wahlberg. "And nobody wanted to talk to Kate Moss, and Calvin was like, 'Just take your shirt off!' "

He then turned to acting, and was determined to be taken seriously. Wahlberg carved out a solid reputation until he was offered the role that made his career — porn star Dirk Diggler — the swinger endowed with more anatomy than intellect in Boogie Nights.

For the movie's more explicit scenes, he wore an impossibly large prosthetic male member that is now so famous he has to hide the object.

"It's in the safe, you know. It's locked away in the safe," said Wahlberg. If he he kept it in his house it would be stolen "before some of my Chagalls. That's serious stuff."

New Family Challenges

With his place in Hollywood secure, Wahlberg next faced both the happiest and saddest moments of his life, both on the same day.

Last September, Wahlberg's girlfriend, Rhea Durham, gave birth to their first child, a daughter named Ella.