At the Browns' training facility. Working out alone. All the way until 6 in the morning.
On a Cleveland squad loaded with stars like Baker Mayfield and Odell Beckham Jr., Sheehy-Guiseppi -- who didn't even play high school football, talked his way into a tryout he wasn't invited to, while sleeping outside because he couldn't afford otherwise -- has emerged as one of the NFL's best stories this training camp.
"I would just describe [myself] as someone trying to chase their dreams, just doing what they love and not listening to anybody else," he said. "Just doing what they have a passion for."
Since signing with the Browns earlier this year, Sheehy-Guiseppi, 24, has captivated teammates and coaches with his extraordinary backstory, unsurpassed work ethic and resilient -- if almost irrational -- mentality.
Improbably, he's now suddenly pushing for a spot on Cleveland's 53-man roster as a return specialist, which general manager John Dorsey affirmed during a Monday interview on 850 AM WKNR. Dorsey called Sheehy-Guiseppi's development in such a short time with the Browns "marvelous."
"The energy he brings to this team is something that you can't really replace," echoed wide receiver Jarvis Landry. "I'm happy he's here. He has an opportunity and he's taking advantage of it."
Sheehy-Guiseppi's path to this point smacks of a movie script straight out of Hollywood.
He initially had dreams of playing college basketball with his brother, Devin. But unlike his brother, Sheehy-Guiseppi failed to make the team at Mesa (Arizona) Community College. Undeterred, he started running track, until a car accident derailed that, too.
"I started lifting a lot. ... that's when I was kind of like, 'I think that football thing is cool,'" he said. "I just liked the roar football gives, and I was just kind of thinking like, 'That's me right there.'"
Without invitation or notice, Sheehy-Guiseppi started showing up to the summer football workouts at Phoenix College, forcing the coaches to allow him to join the team. There, he became an NJCAA All-American in 2016, leading the nation in kick return yards and touchdowns.
Sheehy-Guiseppi fell in love with football and wasn't about to give it up, even after no FBS scholarship offers arrived or calls from the pros came.
Almost three years later, through a friend, Sheehy-Guiseppi said he learned of an NFL scouting workout in Miami. Browns vice president of player personnel Alonzo Highsmith would be there. Sheehy-Guiseppi wasn't invited this time, either. But that wasn't about to stop him. He looked up Highsmith to find out what he looked like and flew from Arizona to Miami. Once there, he sweet-talked his way into the workout by acting like he knew Highsmith, who admitted to the team's website in the spring he "knew nothing about him."
"My mom has given me the knowledge to think outside the box and just trying to use things to your advantage," Sheehy-Guiseppi said. "Meet everybody you could possibly meet and use that to your advantage."
Sheehy-Guiseppi impressed Highsmith with a blazing 40 time of 4.38 seconds, earning an official tryout with the Browns in Berea. Problem was, the workout wasn't for another week. And Sheehy-Guiseppi, out of cash, didn't want to ask his mother, or any other family member, for money. So he signed up for guest passes to get into a 24-hour fitness center during the day, sleeping on grass outside a sports performance facility, where he trained, at night, all while preparing for his chance with the Browns.
"All the work [I] put in, all the moments I was in the gym in Arizona, sleeping in there, just all the moments I stayed up all night thinking," he said. "I wanted an opportunity. To get an opportunity, to make the most of it."
Sheehy-Guiseppi has made the most of it with the Browns and has carried over his eccentric work habits through training camp.
Coach Freddie Kitchens admitted on multiple occasions he's caught Sheehy-Guiseppi working out at the Browns' facility in the morning hours and has had to "send his ass home to get some rest."
Not that Sheehy-Guiseppi always complies.
"A lot of the guys, they be trying to send me home all the time and I be trying to just stay in here," he said. "When they leave, I'm like, 'All right, I'm going to come in now. I know no one's in there at one, so I'm going to go in there at one."
That dedication came to fruition in the preseason opener against Washington. Sheehy-Guiseppi was so excited for his pro football debut that he misplaced his cleats. Beckham, who wears the same size, came to the rescue, offering his.
"He blesses a lot of people with the shoes," Sheehy-Guiseppi said of Beckham. "If anybody wants a pair, he gives them out."
Fortunately for Sheehy-Guiseppi, the cleats were already broken in. Because late in the fourth quarter, his chance to field a punt finally arrived.
"Right before he went out from the sideline, me and Odell [were] talking to him, telling him, you about to take this one to the house," Landry said. "Just catch it first."
Sheehy-Guiseppi nearly didn't. But after briefly bobbling the ball at the 14-yard line, he found a seam down the sideline and bolted away into the end zone.
Before he could really celebrate the touchdown, teammate Ish Hyman clotheslined him to the ground. D.J. Montgomery then jumped on top of him. Virtually the rest of the Browns' sideline followed suit.
"I was gasping for air, but I felt all the love," Sheehy-Guiseppi said. "That was a surreal moment. ... a moment I've been waiting for a long time."
Despite how long he waited for it, Sheehy-Guiseppi didn't bask in the moment for long.
He was back in the facility that night until the morning. The following afternoon, he was still wearing a weighted vest with his helmet on a full hour after practiced had ended. The next day, he was the last to leave the practice field again, catching passes from a jug machine.
"I don't know if I'm an inspiration," he said. "I get inspired by little things -- I can see someone in here working out, sweating and that inspires me.
"If I can inspire somebody to do great things, then I hope they get inspired."