And now that he's a star again, getting ready to play for the Jets in the AFC championship game against the Colts in Indianapolis, he's got a fan club back in Coralville.
"Shonn, he's an inspiration here," said Calvin Taylor, a McGregor's supervisor who worked with Greene that summer. "Everybody's loving it. We call it our own little 'Rudy' story."
Greene is no Rudy. He was a heavily recruited, high-level talent who was supposed to be a star for the Hawkeyes but saw his grades slip when he struggled through his freshman year. Once he was ruled ineligible for 2007, he and Iowa coach Kirk Ferentz put together a plan that would help him recover and return to the field in 2008. That plan included enrolling at Kirkwood and taking the job at McGregor's -- an experience Greene now says was vital to his recovery from the troubled times.
"I think it helped me a lot in terms of my personal life," Greene said. "That's a big part of the reason I'm here right now. It helped me humble myself, get myself together. That time, and working there, it really had an effect on me personally."
"It was about 15 minutes after he started working here, we had the radio on and they started talking about his case," Taylor remembers. "So he's sitting there working with the rest of us, and they're on the radio talking about his status and his position with the team. It was kind of an awkward silence."
Greene kept his head down. When customers would claim to recognize him, he'd tell them they were mistaken. He was a young man who knew he'd put himself in a tough spot and was determined to work his way out of it, rather than use any measure of local celebrity he might have attained to help him skate through it.
"He was a quiet guy," Taylor said. "He didn't talk too much. But then again, he had a lot on his mind."
Greene was dreaming of a return to the field, and he worked hard enough at McGregor's and Kirkwood to earn it. Greene ran for at least 100 yards in each of Iowa's 13 games in 2008, cleared 200 yards twice and set school records with 1,850 yards and 20 touchdowns. That moved him squarely back onto NFL teams' radar screens by draft time, and the Jets liked him a whole lot.
"[General manager] Mike Tannenbaum and all those guys up there, they had a back they couldn't wait for me to see," Jets coach Rex Ryan said. "And when I watched the tape, absolutely, I saw a guy that was just a big, powerful back -- a Big Ten back that just ran hard, great vision, great feet, all the things you look for. But the coach that really stood on the table for him was our running backs coach, Anthony Lynn. He was the No. 1 back on his board for the style of play of our offense."
And so the Jets, who became the stars of the first day of the 2009 draft by trading up to take quarterback Mark Sanchez with the No. 5 overall pick, made another bold move to begin the draft's second day. They dealt all but one of their remaining picks -- a third-, fourth- and seventh-rounder -- to Detroit for the first pick of the third round, and they took Greene with that pick. They explained themselves by saying that Greene stood out, for them, above anybody else they might conceivably take in the remaining rounds.
Nine months later, they're looking pretty good. Greene has come on in recent weeks as much more than a complement to starting RB Thomas Jones. A big, fast, powerful back who can break long runs as well as wear down the defensive line, he's rushed for 135 and 128 yards in the Jets' two playoff games. His 39-yard touchdown run against the Bengals and his 53-yard touchdown run against the Chargers are major reasons the Jets are still alive and one game away from the Super Bowl.
"I think it's his ability to use his size along with his speed," Jets center Nick Mangold said. "If he wants to run somebody over because he feels like doing it, he can do it. And if he wants to break away, he's got that kind of speed, too. So kind of a dual threat."
Greene likes being a dual threat, but he says he'd much rather run away from a defender than through one -- if given the choice.
"That's the best feeling, to break free and have one guy to beat and you're off to the end zone," Greene said. "When you see that, that's a sign of good things to come."
Greene himself could be such a sign for the Jets, who have watched him grow from quiet rookie into valuable playoff contributor in a few short months.
"We used to call him 'The Mute,' because he never said much at the beginning," Jets guard Brandon Moore said. "But he plays with a lot of confidence. He's got a lot of skills -- vision, toughness, and I didn't know he was that fast. He's got fresh legs and the right attitude."
An attitude that may well have its roots in the stock room of a furniture store in Coralville, Iowa.