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Molly Seidel and Jon Green hashed out their grand plan over several cups of coffee.

Not long after she left her Boston-based training group in late 2019, Seidel heard from Green, a friend and former training partner, who wanted to know if she needed help planning her workouts. As someone who was trying to keep his own professional running career alive, Green was familiar with the challenges of striking out on your own.

So they met one afternoon at a coffee shop, where Green spent nearly three hours asking Seidel about her goals and studying her training logs. He wanted to know the types of workouts she enjoyed and the types of workouts that bothered her. She was coming off a long series of injuries, and Green knew they would need to address those problems, too.

“Basically,” Green said, “we talked about everything you could think of.”

Two years later, Seidel, 27, is an Olympic bronze medalist and a crowd favorite in Sunday’s New York City Marathon. One of American distance running’s most captivating and candid personalities, Seidel consistently cites Green — now 26 and considered something of a coaching wunderkind — as a major factor in her success.

“Jon Green,” Seidel said, “is the reason I have a marathoning career.”

Since her surprise podium finish at the Tokyo Games in August, Seidel has had a whirlwind three months while trying to balance her preparation for New York. Green has settled into his new role as the head coach of Atalanta NYC, a women’s running team based in New York, while he continues to work with Seidel, who largely trains alone as a Puma-sponsored athlete.

“You have to look at how we work together as a partnership,” Seidel said. “We’ve been able to support each other as we’ve grown from figuring this whole thing out.”

Seidel and Green knew of each other as college athletes — Green was a Big East Conference champion at Georgetown, while Seidel was one of the country’s most decorated runners at Notre Dame — before they became close friends as teammates for the Freedom Track Club in Boston. They both left the team in 2019.

“It just wasn’t the greatest fit,” Green said.

As they began to work together, one of the first things that Green did was eliminate the speedier workouts that had led to injuries for Seidel. The idea, Green said, was to avoid any training that was faster than 5-kilometer race pace. High volume, though, had never been an issue for her, and that was their primary focus ahead of the U.S. Olympic marathon trials in February 2020.

“Where she excels is doing easy mileage,” Green said, “and a lot of easy mileage. Like, 100-plus miles a week comes really easy and natural to her.”

Yet Green also encouraged Seidel to be honest with him about her aches and pains. She is almost too tough for her own good, he said.

“Molly will not tell me something is hurting unless it’s getting to the point where she feels I need to know,” Green said. “Her ‘3’ on the pain scale is like a ‘9’ for everybody else.”

They both tempered their expectations for the marathon trials, and for good reason: Seidel had never run a marathon. The more realistic aim, at least at the time, was for her to use her marathon training as a base of aerobic fitness ahead of the U.S. Olympic track and field trials later that summer. “Our end goal was to set up for the 10,000 meters,” Green said.

The marathon trials were staged in Atlanta, where Green wanted to be sure that he could follow Seidel’s progress on the course. So he hopped on Craigslist, identified people in the area who were selling used bicycles and asked if they would be willing to rent theirs to him for the day. Green got a lot of “nopes,” he said, before he found one slightly less skeptical gentleman.

“He wanted to know how he would get his bike back,” Green said, “so I wrote up a mini contract and sent him a photo of my license.”

It turned out to be one of the best $30 investments ever: Seidel surged to a second-place finish to secure one of three spots on the U.S. team.

In the wake of Seidel’s triumph in Atlanta, neither she nor Green boarded a rocket ship to fame and fortune. The onset of the pandemic delayed the Olympics by a year. Seidel, who before the trials made ends meet as a babysitter and a barista, added another job to her résumé: working for Instacart. Green, meanwhile, had decided to retire from pro running to pursue a full-time coaching job, but his timing was terrible: No one was hiring. So he helped out at his parents’ hardware store outside Boston.

“So much hand sanitizer,” he said.

As the Olympics came into clearer focus, Green was unsure whether he would be able to watch Seidel race in person because of pandemic protocols. Thanks to some ingenuity and luck, Green found his way to the marathon course in Sapporo, Japan, about 500 miles north of Tokyo, just in time to blow through his cellphone’s data plan as he tracked Seidel’s splits.

Green had positioned himself at a bottle station, and as she made her final loop of the circuit, he shouted “Rule 5!” at her, which was essentially code for: Toughen up! Its origin was from a cycling book that Seidel had read, and it was something that resonated with her through all her training and all her comebacks.

In fearsomely hot conditions, Seidel became the first American woman to win a medal in an Olympic marathon since 2004. Green said he was still not sure whether Seidel had grasped the significance of her achievement. “And maybe she never will,” he said.

In recent weeks, Seidel has alluded to some of the mental and physical challenges of her profession. But she often thinks back to the old days, when she was serving coffee and her coach was working at a hardware store, and she tries to process it all.

“The whole decision to do a marathon was between the two of us,” Seidel said, “and it’s been so fun to see how this has progressed.”