(05-28) 21:31 PDT -- Maybe the feat wasn't quite a full Jack Youngblood, but Aldon Smith showed he can play hurt. That much is as clear as the tattoo on his chest, which quotes from the Book of Psalms: "If God is on my side, why should I fear mortal man?"

Like Youngblood, Smith wore No. 85 and played defensive end. Also like Youngblood, Smith played at a critical juncture on a broken calf bone.

Youngblood gave the Los Angeles Rams a huge lift by playing the entire 1979 playoffs, including Super Bowl XIV, with a broken fibula. Smith gave the Missouri Tigers a similar lift last season when he came back after missing three games.

Smith knew the bone wasn't entirely healed, but the trainers gave him the OK. He wasn't about to miss the Oklahoma game. The Sooners were ranked No. 1, and Mizzou hadn't beaten them since 1998.

Nobody knows whether the 49ers' top draft pick will be a hit - like Andre Carter, who had 12 1/2 sacks in his second season after being picked, like Smith, No. 7 overall - or a miss - like tackle Kentwan Balmer, the last defensive lineman the 49ers took in the first round, in 2008.

Smith would like to work for the Drug Enforcement Agency when his pro football days are done, giving the law a pair of extremely long arms. Friends and family members say he has a fine singing voice and plays the drums for the church choir. It's also known that his pain threshold is very high, he's very loyal to his teammates and enjoys football so much that a broken leg is just an annoyance.

"I came back before it was healed," he said of the fibula. "I didn't want to leave in the first place, I love playing so much."

John Hanna, Smith's roommate and a close friend since they were 5, said, "I could see him limping every day. I was scared because I don't think he was even 75 percent."

A sellout crowd of more than 71,000 people attended the Oklahoma game on Oct. 23. One of them in particular had his eyes glued to Smith.

"I was extremely worried," said Aldon's father, Thurston Smith. "My heart was racing every play. He's a lot like me. He's a competitor. They had never beaten Oklahoma, but I knew he was still hurt. There were a lot of prayers from the stands."

Late in the first quarter, Smith took a step on a pass rush, then stopped, sensing a screen pass by quarterback Landry Jones, intended for the tight end. He stuck a hand up and grabbed the ball - his only collegiate interception - and took off. He stumbled, regained his footing and made the limp disappear. He ran 58 yards before being caught by wide receiver Kenny Stills at the OU 28.

Four plays later, the Tigers scored to take a 14-7 lead. They went on to win 36-27, one of the biggest victories in school history. As thousands of fans poured onto the field afterward, Thurston Smith searched for his son.

"I felt this big, sweaty arm around my shoulder," he said. "I'm holding him up. He was in so much pain."

A teen's decision

As a sophomore at George Washington High in Cedar Rapids, Iowa, Smith was a promising football and basketball player. He was also a young man at a crossroads.

His parents had split up two years earlier. Thurston, an information technician, had moved to the Kansas City suburb of Raytown. Aldon's mother, Kembrya, was about to take a job with a power company in suburban Atlanta.

"He was not doing well in school," his father said. "He wasn't staying focused. He needed some change and focus his mother wasn't able to give him."

Thurston said he offered Aldon a more structured setting, in which a 3.0 grade-point average would be required if he wanted to play sports. That "and being respectful and responsible."

Aldon was 16. It wasn't an easy call. He could have played sports for an Atlanta-area powerhouse in football and basketball if he had followed his mother and younger sister, Rhia.

The decision was complicated because, according to Kembrya, "his relationship with his dad wasn't the best. But I had to give him room to grow."

Whichever way he chose, he would be leaving behind friends and teammates. As a sophomore, he played on the Washington varsity basketball team, which was good enough to upset the No. 1 team in the state, Iowa City West.

"He made us a different ball team," coach Rick Williams said. "You can imagine him being a rebounder on a high school basketball team. He had a defensive mentality. He was long and slender and had a man's strength.

"He was the kind of guy who kept practice loose. He's verbal. He wouldn't shut up. ... He hated to leave and we hated to see him leave."

Smith chose to go with his father to Kansas City. His grades improved, and he became the athlete everybody anticipated. That's not to say the sailing was entirely smooth.

"It was not easy," Thurston Smith said. "At first, he didn't want to follow the rules. We had our clashes. I wasn't bending. I told him he could leave and go follow his mother."

The elder Smith had an advantage when it came to staying on top of his son's academic progress. He handled the computers for the school district, so he could track Aldon's grades on a day-to-day basis. He said he also talked to Aldon's teachers at least once a week.

Smith played tight end and defensive end for the Raytown High Bluejays, who lost four games in his two seasons. His love for football trumped his enthusiasm for basketball, but he could have been a Division I college player in that sport as well.

As accomplished a player as Smith is in both sports, his AAU basketball coach Matt Suther preferred to talk about the kind of person he is outside sports. "He has a really good heart. I think (with the 49ers) he's going to be a great asset to the community. Those are the kinds of things I expect him to be involved in."

Sack happy

"A sack feels like a kiss from a girl you like a lot," Smith said.

In his senior season at Raytown, there was a lot of puckering up. Besides his 12 sacks, he had 60 tackles, 21 tackles for loss, seven forced fumbles, a blocked punt and a safety. At tight end, he caught 34 passes for 570 yards and four touchdowns.

The race among schools for his services came down to Missouri, Nebraska and Kansas State.

On a visit to the high school, Missouri coach Gary Pinkel saw Smith working on a blocking sled. "I just see this guy with this raw ability that's just staggering. Staggering," Pinkel told the Columbia (Mo.) Daily Tribune.

Smith said he picked Missouri because it was close to home and he felt comfortable on the campus. A transcript holdup prevented him from taking part in his first preseason camp. Otherwise, according to Pinkel, he would have played on the defensive line as a true freshman.

As a redshirt freshman, he was practically unblockable in some games. He had 11 solo tackles against Texas and finished the season with a school-record 11 1/2 sacks. The previous record of 11 was held by the 49ers' Justin Smith.

One of Aldon Smith's sacks came at the expense of fellow 49ers draftee Colin Kaepernick in a 31-21 Missouri win over Nevada.

During that season, Pinkel told the Daily Tribune, "I was thinking, 'We may not get three years out of the guy.' "

Last season, Smith's sack total fell off to 5 1/2, but he had 48 tackles, including 10 for loss. His hit on Kansas State quarterback Carson Coffman caused a fumble that teammate Jacquies Smith returned for a 53-yard touchdown, the pivotal play in Missouri's 38-28 win.

Going pro

Until the NFL draft advisory committee weighed in, Smith wasn't sure he would leave after just two college seasons. The panel considered him a second-round draft pick; that was good enough for Smith.

"They're usually very conservative," he said. "I thought that meant I could go in the first round." Leaving Missouri, though, was another tough call. "I loved school," he said. "I loved being on the campus. I loved the football life."

He's fine with the 49ers' plans to make him an outside linebacker. Now 6-foot-4, 265 pounds, he plans to play at 255-260. He said he will be coming to the Bay Area this week to join with some of the 49ers in informal workouts during the owners' lockout.

His father had hoped he would finish school and didn't agree with the decision to leave early. But when Smith was the seventh overall pick, it assuaged his doubts.

"Parents don't always have the right answers," Thurston Smith said.

His mother said she wasn't surprised that he went in the first round. "He gave more than he had to football," she said.

She recalled trying to help him with his penmanship when he was younger. She wanted him to write bigger. It doesn't matter, he told her. "My name is going to mean something someday."