A GENERATION or two ago, in the cartoonish television action series “The A-Team,” Bosco Albert Baracus clomped along the edge of civilization like Sasquatch, half-man, half-myth. Animated by Mr. T in a Mohawk and enough gold jewelry to buy Trinidad and Tobago, B. A., as he was called, was a fool-pitying mercenary whose temperature was often at a steaming boil.'

Doug Curran/20th Century Fox

In “The A-Team,” based on the old television action series, Quinton Jackson plays B. A. Baracus, the character made famous by Mr. T.

The show centered on the escapades of B. A. and three other Special Forces operatives, most of whom had robbed the central bank of Hanoi under orders, and all of whom were on the run from the military. As happens more often than not in such situations, the fugitives escaped to Los Angeles, where they battled injustice by hiring themselves out as soldiers of fortune. More often than not, they worked pro bono for downtrodden D-Teamers.

“B. A. Baracus was my childhood hero,” recalled Quinton Jackson, a 31-year-old martial-arts fighter who still answers to his childhood nickname, Rampage. “He used to say his initials stood for Bad Attitude. I used to have a bad attitude too.” Mr. Jackson, it turns out, is a master of understatement.

He reinterprets the role in the $100 million cinematic version of “The A-Team,” which opens Friday. This time around, B. A. and the renegades run covert missions in Iraq and get snagged in a plot so tangled and discursive that you might need a map and a compass to stay on course.

The new “A-Team” is basically a buddy-buddy-buddy-buddy film. “We’re a band of kooky guys who have certain skills,” said Liam Neeson, who takes over from George Peppard as the master tactician Col. John Smith — Hannibal to his friends. “All together we have an incredible skill of taking on dastardly deeds and daredevil stuff that no one else would attempt.” (Rounding out the rule-breaking quartet are Bradley Cooper as Lt. Templeton Peck, a k a Face, played by Dirk Benedict in the show, and Sharlto Copley as Capt. H. M. Murdock, better known as “Howling Mad” Murdock, previously embodied by Dwight Schultz.)

As before, B. A.’s particular expertise is vehicular; in this case involving getaway vans and a parachuting tank. “B. A. is a great mechanic who can fix anything,” Mr. Jackson said. “In real life I can’t fix a sandwich. All we have in common is that we’re hard dudes with soft hearts.”

The unyielding scowl of Mr. T’s B. A. invited alteration with a brick. Mr. Jackson’s update always has a smile on his face, a combination of the innocent and diabolical.

Then again, how could he not smile during his character’s prison epiphany, which comes after he reads a self-help book called “Compassion and Forgiveness”? He lets his Mohawk grow in and goes all Gandhi on his A-Teammates.

“I was impressed that Rampage pulled it off,” Mr. Neeson said. “He doesn’t grandstand. He’s just simple and truthful, and what comes out of his mouth you believe.”

Mr. Jackson has plenty of what the critic Kenneth Tynan said is essential to great acting: the ability to communicate a sense of danger. “With Rampage that danger is legitimate,” said Tom Rothman, co-chairman of Fox Filmed Entertainment, the studio behind “The A-Team.” “He has lived what most actors pretend.”

Until now Mr. Jackson’s emoting has been mostly confined to the Octagon, the caged ring in which the Ultimate Fighting Championship pits mixed-martial-arts combatants. Once condemned by Senator John McCain as “human cockfighting,” mixed martial arts is a savage, free-form affair that allows a wide variety of combat styles, including boxing, wrestling, kickboxing and Brazilian jiu-jitsu.

Mr. Jackson’s signature body-slam — deemed the hardest blow in all of professional sports by the television show “National Geographic’s Sports Science” — usually has the proper chastening effect. No doubt it’s a fairly fearsome sight to behold a man the size of a tobacco warehouse lunging at you. “Rampage’s hands are huge and have a deep, deep strength,” Mr. Cooper said. “They’re like something out of Greek mythology.”

Mr. Jackson’s entire body seems to have been hammered on the anvil of the gods. His abs are laddered; his torso is bound by ropelike veins; his biceps look like grapefruits dosed with Miracle-Gro.

Mr. Jackson, who is a former Ultimate Fighting light-heavyweight champion, is not only large, but also impressively decorated. The tattoo on his right arm reads, “Rampage God’s street soldier.” The panther that prowls down his left arm masks a smaller “Rampage” tattoo he inscribed himself when he was 15. “I covered the first one up because the letters were crooked, and I almost misspelled my name,” he said. “I’d be embarrassed to be on TV with something that ghetto.”

Mr. T. used to say that when he was growing up in a housing project on the South Side of Chicago, his family was so poor it couldn’t afford to pay attention. Mr. Jackson was raised in a grim section of south Memphis, where drug dealers operated openly.

At 8 he befriended a con artist who employed him as a bag boy. He’d sit on a street corner with crack in a Skittles bag. If a police officer appeared, he’d heave the bag over his shoulder. “Even back then I knew the law,” he said. “If the crack was at least 15 feet away from me, I couldn’t get busted.”

 

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 Trailer: 'The A-Team'

Since then he has been busted twice. While he was on the wrestling team at a community college in Northern California, he was charged with assaulting a teammate who had allegedly slugged him in the face with a phone. (Mr. Jackson, who was later put on probation, said the brawl began when he chewed out the man for talking trash to his own mother on the same phone.)

Two years ago he was arrested at gunpoint not far from his home in Irvine, Calif., after plowing his pickup into three vehicles and narrowly missing several pedestrians and bicyclists. Though Mr. Jackson’s name and picture were decaled on both sides of the truck, he led police on a high-speed chase through Newport Beach.

Mr. Jackson now says he was depressed, sleep deprived and hadn’t consumed anything but Throwdown Rampage Punch energy drinks for four days.

“I don’t see myself doing anything crazy again,” he announced in January after being sentenced to three years’ probation for reckless driving. “I want to be a positive role model.”

Especially, he said, to his four children. Two of his boys have the middle name Rampage. His daughter, Naname, had to settle for Page. “I compromised with her mom,” Mr. Jackson more or less explained. “She wouldn’t let me call her Rampagea.”

Mr. Jackson sets up his punch lines as carefully as his punches. On the first day of the “A-Team” shoot he sidled up to Mr. Copley, a Johannesburg native, and said, “You’re from South Africa, right?”

Mr. Copley sighed audibly. “I thought, I’m a white South African, and this conversation is going to go down a political road,” he said. “I was about tell Rampage that my best friend back home is black and gay, when he said, ‘You should apply to be a United States citizen.’ ”

Why’s that? asked Mr. Copley.

“Because then,” Mr. Jackson reasoned, “the two of us will be the only African-Americans in the movie.”