“With 150 meters to go, I was close to third and thinking, ‘Do not leave here without that hardware,’ ’’ said Centrowitz, who finished in 3:36.08. “There’s a big difference between third and fourth. I was just digging. Right when I crossed the line, I was in disbelief. I’m holding up three fingers and I’m like, ‘Did I get third?’ ’’

Disbelief turned into elation when Centrowitz confirmed he earned bronze, becoming the youngest American to win a medal in the 1,500. The 22-year-old gave up his remaining NCAA eligibility at the University of Oregon in November and signed with an agent.

Tonight at the Reggie Lewis Center, Centrowitz will make his professional debut in the New Balance Indoor Grand Prix in the men’s 3,000-meter race. The field includes Ethiopian Dejen Gebremeskel, defending champion in the event and bronze medalist in the 5,000 also at the 2011 world championships. The start lists for the meet are stocked with medalists from the Olympics and world championships. And competitors eye strong starts to the indoor track season with this summer’s London Olympics in mind.

That said, Centrowitz doesn’t want to get too far ahead of himself. He hopes to improve on his 3,000 meter personal best of 7:50.59. But with Gebremeskel’s personal best at 7:35.37, Centrowitz says he would have to have his A game to win and anything close to Gebresmeskel would be a success. Competing in the 3,000 is a chance to build strength for shorter distances. He will compete in the NYRR Wanamaker Mile at the Millrose Games Feb. 11.

Since high school Centrowitz has succeeded by setting goals that follow a gradual progression. That meant setting his sights on college conference titles, then NCAA titles, the US championships.

“Winning the bronze medal definitely exceeded my expectations,’’ he said. “In terms of changing now, once you get to that level, you want to be consistently winning medals. You don’t want to fall off the map the next year or the next couple years. Now that I’ve got that success so early, instead of being a consistent threat for four to six years, it’s maybe the next six to eight, maybe even more. I plan on running until at least 2020.’’

While his bronze changed his goals and his career trajectory, Centrowitz kept much of his daily life the same. He still attends class, working to complete his degree in sociology. He still trains under Andy Powell, Oregon’s associate head coach for men’s track and field. During tough times early in Centrowitz’s collegiate career, Powell was there with support and encouragement. And the two East Coast-bred runners (Centrowitz attended Broadneck High School in Annapolis, Md.) quickly bonded. Now, Centrowitz sees Powell like a big brother.

“He had an excellent year last year and we didn’t want to change too much because it’s an important year with the Olympics,’’ said Powell, who was a standout at Oliver Ames and Stanford before his coaching career. “I typically don’t coach post-collegiate, but this is one of those special situations. He’s a real special athlete.

“He’s one of those people who likes to race a lot, so we’re trying to find a lot of good races for him. He does well in championship-type races that are a little bit more tactical. We’re going to take one race at a time. It’s nice running a 3,000 in Boston, a little out of his element, double the distance of what he’s used to. We want to have a good showing here in Boston and kick off the year well.’’

Centrowitz attributes his breakthrough at the World Championships to good coaching, good genes and good health. His father, Matt, was a two-time Olympian, qualifying for the 1976 Montreal Games in the 1,500 and the 1980 Moscow Games in the 5,000. His mother, Beverly, ran at Hunter College and posted a personal best of 2:08 in the 800. But it wasn’t until he recovered from foot injuries in 2009 and 2010 that Centrowitz displayed his natural talent on the world stage.

“Last year, was my first year in a while of being healthy for a consistent time,’’ he said. “When you’re consistently healthy for a long time, the training just starts to snowball and you see results a lot bigger than when you take breaks because of little injuries.’’

Centrowitz plans on putting in as full an indoor track season as possible, then carefully choosing outdoor races in the lead up to the US Olympic track and field trials in June.

“The US is so deep in the 1,500 you can’t overlook the trials,’’ he said. “In terms of me trying to do what I did last year, I didn’t even think about the world championships last year. I just was dead set on the US championships. Once you finish that race, you can kind of reassess. My main focus is on the Olympic trials. If you make that team in the US, it’s so good now that anyone can be a medal contender from the US.’’

Shira Springer can be reached at springer@globe.com.