The petite 16-year-old, who claimed her second consecutive US all-around title earlier this month, kept her closest challenger, Gabrielle Douglas, at bay with a strong performance in her final routine of the night.
Despite coming agonisingly close to stepping out of bounds on the floor exercise, Wieber delivered an otherwise superb display for a score of 15.400 in front of a near-capacity crowd of 12,220 at the HP Pavilion.
She ended her high-octane routine with a double twisting, double back mount as the fans erupted with ear-splitting applause.
That gave Wieber an overall total of 61.700 to head the standings in the two-day competition with Douglas second on 61.400 and Alexandra Raisman third on 60.300.
"Overall everything went pretty well today," Wieber said. "My main goal was just to come in and be confident and hit four strong routines and I feel like I did that.
"There were definitely some areas I want to improve on though. On beam. I had a few missed connections and some wobbles here and there. I know that routine has a lot more potential."
Douglas, nicknamed the 'Flying Squirrel' due to her astonishing ability on the uneven bars, made an error on her favourite apparatus when she stalled on a pirouette but she somehow held on to the bar before earning 15.250.
Though she recovered well in the later routines, even she was surprised by how she managed to avert falling off in her first event of the evening.
"I just like stopped in mid-air," said the bubbly Douglas, who finished second behind Wieber in the US all-around earlier this month. "And I'm like, 'Come on, I'm still going to do this.
"Man, I was using every single muscle. I was like trying to pull my feet and then I made it and I was like, 'Whoo! The routine is not over yet. There are five more skills.' I just pulled it out of nowhere."
With five spots on offer this week for the London Games, Kyla Price was fourth overall on 59.600 with Kyla Ross fifth on 59.400.
The winner of the women's all-around competition will earn automatic Olympic selection and, for the first time since 2000, the rest of the team will be decided after the second day of competition on Sunday.
Wieber, who was perhaps the only gymnast of the 14 who did not succumb to nerves on Friday, has all but sewn up the sole guaranteed spot.
"It definitely gives me a little confidence but at the same time knowing I still have another whole day of competition... I have to keep the focus going and try to improve on Sunday," she said.
Douglas, widely touted as Wieber's likeliest challenger for the all-around crown at the London Games, was also in upbeat mood.
"I am just feeling very confident," said the 16-year-old. "I obviously made a couple of mistakes here and there but we're human and that's what training is for.
"So I am going into tomorrow really strong and I'll just polish up my skills. I do want the top spot very badly, but I'm trying not to think about being first."
Former world all-around champion Bridget Sloan had her Olympic hopes dashed when she pulled out after spraining her left elbow during practice.
"It's hard to accept but, at the same time, I know that it was meant for me to be done," the 20-year-old said.
"Everything happens for a reason. Again it's hard but...," she then trailed off as the tears began to flow.
Nastia Liukin, who won the 2008 Olympic all-around title, endured a difficult evening after earning just 14.050 from her first routine on uneven bars when she stalled on a handstand with her legs folding over.
Though she did not fall off, she lost momentum and crashed to the mat on her backside with her dismount.
"Of course I didn't have the best routines but I proved to myself that anything is possible," said Liukin, who finished the opening day 13th in the overall standings. "Whether or not it is my last competition, I'm just excited to be here."