"Once a guy gets in, you see who he is and where he's going," Hart said. "Josh grew on me."
After a while, Byrnes was an intern by title only.
"He did a little of everything," said Shapiro, the president of the Indians after serving as GM from 2001 to 2010. "Josh made an impact on all three of us with just how talented, how smart, how disciplined and how passionate for the game he was."
If only tackling the Midwest winter and all its tidings came as naturally.
For as well as he handled himself within the confines of the Indians' cozy offices, Byrnes -- no thin-skinned soul, having grown up on the East Coast -- essentially had no shot when it came to braving the bitter cold of an Ohio winter.
Take the time he was looking for an apartment and learned a lesson in perseverance instead.
"It was a snowy night, where you couldn't see anything, and I took a wrong turn," Byrnes said. "All of a sudden, my Honda Civic is stuck. ... It feels like I'm in the middle of a lake, but I couldn't see anything because the weather was so bad.
"I walk up this hill, through a rough neighborhood -- this is before we had cell phones. I called AAA, and they said all their operators were busy. I finally got a couple of guys to come and help. We're rocking my car in and out of its hole."
The car eventually moved, and so did Byrnes -- not just down the street on this blustery night but, more important, up the organizational ladder, as he went on to become a scouting director at age 27 and later the GM of the D-backs in 2005 at age 35.
Today the 41-year-old Byrnes is a GM again, this time for the Padres, replacing Jed Hoyer, who will rejoin his former Red Sox boss, Theo Epstein, with the Cubs, in the same role he had in San Diego for two seasons.
"My instincts are that this will be right up Josh's alley," Hart said this week.
Byrnes is certainly no stranger to the Padres, having spent the past 10 months with the team as a senior vice president of baseball operations, assisting with several areas of the front office: helping Hoyer, lending a hand in scouting and player development, and helping on the business side, working with team president and COO Tom Garfinkel.
But to those who know him best, from those he's worked both with and for during his days in Cleveland, Colorado, Boston and Arizona, and now San Diego, Byrnes is back in the only job he's ever wanted -- GM.
"So many people you see get that job and are miserable in it. Josh is not," Shapiro said. "The one thing that stands out for me is how much he enjoyed that role. He enjoyed all aspects of that job.
"He's a good leader, he's passionate about building a team [and] a roster, and he is a tireless worker. To me he has all the attributes to be a great GM."
Byrnes will lean on the lessons of the past, his past, as he goes about plotting the future of the Padres, who lost 91 games in 2011 and will likely have a payroll between $53 million and $55 million, according to vice chairman and CEO Jeff Moorad.
There is considerable work to be done.
Hoyer, before moving to Chicago, wanted to add a corner outfielder with a productive bat, he wanted to bolster the rotation and he wanted to get back to a concerted focus on run prevention, which was the hallmark of a team that won 90 games in 2010.
As for Byrnes, he has no doubt spent the past week or so developing his outline of how he wants to attack the offseason. And as much as this unanticipated twist in his career appears, Byrnes won't be caught flat-footed, by any means.
Byrnes has been praised for his preparedness, his organizational skills and his ability to think fast on his feet. While in Cleveland, he was instrumental in pushing for the use of video for advance scouting as well as computer software integration.
When he says he values statistical analysis and traditional scouting equally, he's not merely giving a politically correct answer to what has become a tired question for wannabe front-office types. He values both.
"The one thing he believes in and preaches is looking at things from all angles; that you can't stay in the same lens the whole time," said A.J. Hinch, assistant GM for the Padres, who was Byrnes' manager with the D-backs.
"He's willing to adapt to that change. He's not one-dimensional. It's a characteristic he gives his people. It's a characteristic he lives by."
Byrnes figures to use many of the influences he's had in his career when he finally takes control of the Padres' baseball operations department, lessons he learned from Hart, O'Dowd and Shapiro in Cleveland. Byrnes later went to work for O'Dowd in Colorado before moving to Boston, where he worked with Epstein.
"I think I've borrowed something from all of them," Byrnes said. "These jobs are tough. There's a common link [with my influences]. There's a lot of passion, a lot of fairness ... These are jobs you can't do if you're afraid of failure."
Not, of course, if you ever intend to be a GM again.
Byrnes, of course, has been down this road before. He spent 4 1/2 seasons as the GM of the D-backs before being dismissed on July 2, 2010, with five-plus years remaining on his eight-year contract.
In 2007 the D-backs won the National League West and advanced to the NL Championship Series with a roster filled with talented, controllable players. Three seasons later, the D-backs, with many of the same players, were torpedoed by one of the worst bullpens in recent memory, and tumbled precipitously to the bottom of the division.
"But that's how narrow it is between winning and losing," said Byrnes, who certainly had an imprint on the 2011 D-backs, who surprised everyone by winning the NL West. "There's a human element to all of this."
While with Arizona, Byrnes traded for Dan Haren, hoping to pair him with 2006 NL Cy Young winner Brandon Webb, but Webb's right shoulder never obliged. He traded for center fielder Chris Young, traded away Carlos Gonzalez and Carlos Quentin, and later made a deal that landed Ian Kennedy, who won 21 games this past season.
Some decisions worked, some didn't.
"That's all part of the experience," said Hart, an analyst for MLB Network. "I think it will make him better. He'll look at some things he did as hitting a home run. He'll look at some things that he could have done better. That's a part of growing and being successful.
"I did it for 16 years, and you're not flawless. You're dealing with ... guys who are overachievers, guys who underperform. Something I learned 40 years ago was that you just keep going."
Some pundits thought that the decision to dismiss Byrnes was one of panic. Others felt that change might have been best for the D-backs.
"I've always been hard on myself. Some of the decisions we can maybe second-guess, but I think that the overall strategy was sound," Byrnes said. "Some years it works, some years it doesn't. I understand it's the nature of the business.
"But in the end, we didn't win enough to quiet down the criticism."
Following his dismissal, Byrnes scooped up his family and went to Hawaii for a hastily arranged vacation. It was a chance to spend time with his wife of 10 years, Charity, and their two daughters, Avery and Darby.
It was a chance to step away from the game -- until the game kept on calling him. True to form, too, Byrnes kept answering.
"The rest of us can go on a vacation, and we can turn our brains off," Charity Byrnes said. "But Josh is too competitive for that. He doesn't function any other way. It's in his blood.
"Josh would go on the water slide with our oldest daughter and then talk to Theo. Or he would go kayaking and then talk with [Hoyer]. He was happy to do it."
From watching Orioles games at Memorial Stadium as a kid to analyzing the swing and every move of his favorite player, Eddie Murray, to innumerable games of Strat-O-Matic with friends, baseball has been in Byrnes' blood for as long as he can remember.
It's not a profession for him, but a passion, one that has included several twists and turns since that first winter in Cleveland.
"Josh was not a big fan of the Cleveland winters, so once we had some snowfall, and we completely buried his car. You couldn't see the car at all," said Bart Swain, the Indians' director of baseball information, who roomed with Byrnes in 1994.
"About a week later, he got all of our keys and moved all of our cars ... hiding them all around the neighborhood. We had no idea where they were."