Hasim Sharif Rahman, who shocked the sports world last weekend by winning the heavyweight boxing crown, once was a tough kid in a tough neighborhood whom police dismissed as a street thug.

But Rahman heeded a warning from a judge who offered probation over prison. The young man left the city for a training camp at a Catskills resort in upstate New York and devoted himself to his boxing career.

Now, after his fifth-round knockout of Lennox Lewis in South Africa on Saturday night (Eastern time), the 28-year-old known as "The Rock" (his surname is pronounced Rock-mon) has become Baltimore's first heavyweight champion. He returned to a rally at City Hall complete with a boxing ring in the plaza being proclaimed as a role model for the city's youth.

He attributes his lifestyle change to the June 1991 birth of his first son, Hasim Jr., and his close call in court.

"When I had my son, I felt like I owed him a good chance at life, an honest chance at life," Rahman said in an interview with The Sun yesterday. "If I didn't change, I would be in somebody's penitentiary or somebody's graveyard."

The boxer has escaped the odds in more ways than one. He nearly died a decade ago when a friend's speeding pickup truck flipped, killing the driver and pinning Rahman's face under the gas tank, leaving an ugly scar on his right cheek. In the early 1990s, a street fight led to gunfire, and Rahman survived five bullets, several of which hit him in the stomach.

"This is an obvious success story," said police Maj. Russell N. Shea, who arrested Rahman twice. "He went from the drug world to the boxing world."

Rahman said he was "an immature, confused father who had to grow up in a hurry." He met with his mother, Joyce, and his wife, Crystal, and told them he was committed to change. "We're too smart to be following the crowd," he told them.

The man who earned a reputation as an iron-fisted street brawler is now a family man who broke training two years ago to make his daughter's 1st birthday, even though the interruption cost him a victory. Oleg Maskaev promptly knocked Rahman out of an Atlantic City, N.J., ring two weeks after the party.

The man who once strayed now goes on radio shows to promote the "I Can, We Can" drug rehabilitation center, directed by his uncle, Israel Cason.

Rahman is living up to his Muslim name, which means "one who crushes evil."

The real test

Now the next test for Rahman begins. He earned $1.5 million when he took Lewis' World Boxing Council and International Boxing Federation belts; his next fight could be worth millions. The late night talk shows are already calling; the boxer chose Leno (tomorrow night) over Letterman. The governor proclaimed yesterday "World Heavyweight Championship Day in Maryland."

And at a rally Monday, fans fought for the privilege to pour water down his throat, like ringside corner men.

"He's going to be under a microscope," said Lawrence B. Rosenberg, who has been Rahman's attorney for the past 13 years. "I hope he's ready for it. Going from nothing to something that quickly is hard to deal with."

The boxer says he will remain an earnest husband and father. He and his wife, Crystal, live in Abingdon in a two-story, $200,000 house with their two sons, Hasim Jr., 9, and Sharif, 4, and daughter, Amirah, 2. The oldest boy just brought home a report card with four A's and two B's, and wants to be a doctor like his uncle.

Rahman also took in his 15-year-old nephew, Terry Frierson, whose father had died. "He's tough on me in school and everything, to guide me in the right direction," Terry said of Rahman.

Added Rahman: "Whatever I have to say to my children, whether it's calling them from downtown Baltimore or somewhere else, they listen. It carries weight."

Rahman's competitive streak goes back to when he was in the third grade. "If you're playing him in cards, and you win, he will not let you leave until he wins," said his cousin, Aisha Ali, 27.