SANTA CLARA -- Ahmad Brooks is someone you'd want walking with you through a dark alley. He's 6-foot-3, 260 pounds and nearly as fast as he is intimidating. On top of that, his track record off the field proves he has a mean streak.

Many men would bask in such a rugged glow. In the age of the fake tough guy, Brooks is the $2 steak that Jim Harbaugh talks about. Yet, he shies away from the persona. He evades the thug stigma like he does most blockers.

"I'm not walking in alleys," he said this week. "We're better than that. We ain't going to stoop down to that level, even if we have before. We're not walking in alleys. We're going straight through the front door. That's being grown."

San Francisco 49ers’ San Francisco 49ers’ Ahmad Brooks (55) leaps and is called offside against the Carolina Panthers in the second quarter of
San Francisco 49ers' San Francisco 49ers' Ahmad Brooks (55) leaps and is called offside against the Carolina Panthers in the second quarter of their NFC divisional playoff NFL game at Bank of America Stadium in Charlotte, N.C., on Sunday, Jan. 12, 2014. (Jose Carlos Fajardo/Bay Area News Group)

Brooks had some growing to do, as trouble seemed to follow him. He was dismissed from the University of Virginia his senior season for undisclosed reasons. In 2008, while with the Cincinnati Bengals, he was accused of punching a woman in the face. Six months ago, Brooks reportedly attacked teammate Lamar Divens with a beer bottle.

Today he is an unsung hero on a Super Bowl contender, having made the Pro Bowl for the second consecutive season. He is a half a sack from the 49ers' single-postseason record. He is a player his teammates and coaches speak about with respect and regard.

He has manned up, taken his lumps, and become better for them.

"Ahmad's a very good person," defensive coordinator Vic Fangio said. "You're always happy for a good guy to experience success. He was a guy when I got here I thought had a lot of ability and potential but for some reason never fulfilled it in Cincinnati and hadn't fulfilled it here. But I saw it in him. ... He had to dive into it full-bore with his focus and his effort, and he did that."

Brooks, 29, doesn't shift blame for his off-field problems. Instead, he points out how he has matured.

"The things that I've done, that's just history," he said. "Anybody can go back and read what I've done. But at the end of day, we've all had our mistakes. The key is how you overcome them."

Brooks is still an NFL linebacker, and a good one. So the relentlessness, the aggression, the desire to crush another human, is still there. But that stuff is on the field. Off the field, knowing another mistake could cost all he has built, he has opted to be a grown man.

His voice carries a note of irritation when he talks about the public's perception of him. He said he doesn't follow media reports about himself and can't tolerate too much social media, where records are never expunged.

But he has found vindication.

He has gone from a third-round pick in the 2006 supplemental draft to a second-team All-Pro selection, from possibly squandering his potential to releasing it full-bore off the edge of the 49ers' defensive line.

He said having Patrick Willis, NaVorro Bowman and Aldon Smith count on him as a crucial element of their elite linebacker corps is especially fulfilling.

But most fulfilling, he said, is the admiration with which his princess looks at him. That's enough to make a man be better.

"She's about to be six. I've got to be a parent to her," he said. "I'm waaaaay more mature. I'm about to be 30 years old. I had to mature."

Contact Marcus Thompson II at mthomps2@bayareanewsgroup.com. Follow him on Twitter at twitter.com/ThompsonScribe.