While in Illinois on Jan. 16 and 17, he and his parents met with head coaches from USC, Tennessee, Florida and LSU.
His parents talked openly of their admiration for LSU coach Les Miles and the school's history of success with multi-sport athletes.
Coaches from all of the schools still recruiting Jackson have offered their word that he can participate in track and field during the spring.
Jackson, too, before the visits, said he was most excited to see Miles.
A fan of Illinois basketball as a kid, Jackson liked the Tigers in football. He wanted to play like Tyrann Mathieu, according to Williams-Keene. She said he was "like a kid in a candy shop" when LSU offered a scholarship.
Alongside LSU, USC re-emerged as a leader after the push engineered by new coach Steve Sarkisian. UCLA coach Jim Mora made his visit to see Jackson in Los Angeles on Jan. 27. That day, as many as eight UCLA football and track coaches spent more than half of the school day at Serra.
"I kind of feel bad for him," Serra athletic director Ted Dunlap said. "It's like saying I feel bad for Michael Jordan because he couldn't go out to dinner or go to the beach. But it puts a ton of pressure on an 18-year-old kid.
Biggs, the track coach, watched from afar as the coaches descended on Serra last week.
"You could see it bothered him," Biggs said. "He wasn't smiling."
Williams-Keene said she thinks her brother "has a handle" on his decision. Many others close Jackson said they believed he was torn.
"In quiet moments," Biggs said, "he's like, 'Man, what am I going to do?'"
To complicate matters, an undercurrent of skepticism lurks between Jackson's parents and the coaches at Serra.
Christopher Jackson said he's concerned the high school coaches want to see his son stay in Los Angeles at the next level.
Not at all, said Altenberg. The coach said he never offers his recommendation; only support.
Altenberg does not know Jackson's parents well. They've met three times, the coach said, and talked for a few minutes each visit.
"They really trust us," Altenberg said, "because we take care of him."
In the middle, 31 months after that fateful meeting at the restaurant, stands Jackson with his made-for-California personality, laboring until the end over this decision, but nonetheless composed as usual. He said he feels no pressure from his coaches and knows that his parents want what's best for him.
"He's living it," Altenberg said. "He eats it up. And that's one thing I love about him. Everything he does, he just enjoys it.
"A different kid who wasn't so smart, this could have been a hot mess."