Although hats representing all five schools initially were situated on a table in the Simeon gym, Parker pulled out a Duke long-sleeved T-shirt while announcing his decision.
Duke coach Mike Krzyzewski has had good luck with recruits in his native Chicago. He also landed Jon Scheyer (Glenbrook North), Sean Dockery (Julian), Michael Thompson (Providence) and Corey Maggette (Fenwick) from the area.
"What brought me to the decision is, of course, the history," Parker said. "Duke was always going to be a team in the tournament. You can't go wrong at the program. And most importantly, the long-term investment -- I feel if I go there, I can get a good degree.
"I can also stay close to home, where it's easily accessible for my parents, for my family. It's not too far away. And it's just Coach K -- that's one of the best coaches ever, and I wanted to be able to experience the things that he has next year."
Parker said he called Krzyzewski and Duke to inform them of his decision.
"He said congratulations," Parker said. "(Duke was) pretty excited. I know (I'm) not in their mind. They land players like me all the time."
The official visit to Duke was not Parker's favorite recruiting trip, he said.
"To tell you the truth, that was probably the worst on-campus visit I had," Parker said. "It was just because I didn't do what I wanted to do, which was be a kid. But I know being at college is all business, and that's what they wanted to show me. I know I didn't have a good time, but they just wanted to tell me and prepare for me and give me a little bit of taste how it is going to be in college."
Parker said the final decision came down to Florida, Michigan State and Duke. He admitted that choosing Duke over Michigan State and longtime Spartans coach Tom Izzo was "difficult."
"(Izzo) has been recruiting me ever since I was a freshman in high school, and he's been to most of my games," Parker said.
"But a lot of things went into it like, 'How will I be used on the floor?' (Spartans forward) Branden Dawson and I play the same position, and it would be kind of a controversy if me and him were on the same floor and we run into each other. I just wanted to go to a school that was fitting for me."
Parker also acknowledged that he has seriously considered staying in college for more than one year.
"I may play in college for two or three years," he said. "It doesn't matter to me. I just want the college experience. The most important thing is getting the degree, and I want to go to school."
Parker is Simeon's biggest recruit since Derrick Rose, who was ranked No. 5 in the Class of 2007 and attended Memphis before becoming the No. 1 overall pick by the Chicago Bulls. Nick Anderson, Bobby Simmons and Ben Wilson are also among the players who have attended Simeon.
Parker's recruitment was kept to a tight circle. Only Parker's father, Sonny Parker, a former NBA player; his mother, Lola Parker; and Simeon coach Robert Smith handled his recruitment. College coaches weren't allowed to have Parker's cellphone number. They had to go through his parents to talk to him.
"All of them are great programs," Sonny Parker said about the finalists. "Jabari just wants to play. He wants to win a national championship, of course, but he wants to graduate from college. All the schools are he picked are great schools."
His mother said she was sometimes unsure which school her son would pick.
"I don't think I've always known, because we've raised Jabari to make choices," she said. "Believe me, he just whispered to us in that room before we walked out. I and Sonny raised him to make decisions like that, because he's going to school there. Not us."
As a junior, Parker was named the ESPNChicago.com Player of the Year, Illinois' Mr. Basketball and the national Gatorade Player of the Year. He averaged 19.5 points, 8.9 rebounds, 4.9 assists, 3.3 blocks and 1.4 steals a game.
Parker and Simeon have won three Illinois Class 4A state championships. The Wolverines are attempting to become only the second team in state history to win four consecutive titles.
Parker's senior season has been a rocky one. He fractured a bone in his right ankle in July while playing for Team USA in the FIBA U17 World Championship tournament. Without having practiced since the injury, he decided to play in Simeon's season opener Dec. 1 and noticeably struggled while playing 10-plus minutes. He also played in the team's next two games.
Parker did sit out Simeon's game Monday and is expected to miss at least a few more games while continuing his rehab and conditioning. He could return for the Pontiac Holiday Tournament at the end of the month.
Parker is the fifth Simeon senior to commit to a Division I program this year. Kendrick Nunn and Jaylon Tate are Illinois recruits, Kendall Pollard is going to Dayton and Quron Davis is headed to Chicago State.
Parker played on the club circuit for the Mac Irvin Fire, whose alumni include Juwan Howard and Antoine Walker. Whitney Young center Jahlil Okafor, the No. 2 junior in the country, has been teammates with Parker on the Fire.
Parker is the third top-5 prospect to come out of Chicago in the past six years after Rose, who was No. 5 in 2007, and Anthony Davis, the top recruit in 2011. Both players went to play for John Calipari -- Rose at Memphis and Davis at Kentucky.
Parker was ranked No. 1 in the senior class until Andrew Wiggins reclassified from the Class of 2014 into the Class of 2013 in October.