On Sunday, he snaps for the undefeated Patriots, often delivering perfect strikes for Pro Bowl kicker Stephen Gostkowski and punter Ryan Allen. During the week, he practices with the team and attends meetings, but when most of his teammates go home after a long day, Cardona often doesn't.
That's when he heads to his other job, working at the Naval Preparatory Academy in Newport, R.I., as part of his duties as an active member of the Navy.
"It's long days, and there are not really any days off, but the balance has been good," Cardona said. "It's a lot of tough work, but I'm lucky to be out here and getting this opportunity."
Cardona, 23, is the only active player in the NFL who is also an active member of the military, which is a neat story to relay any day, but especially on Veterans Day.
"He's serving in the Navy, so he does what he's assigned to do, and within that we've been able to work with that schedule to keep him participating on our team," head coach Bill Belichick said.
"So he's balanced them. It's hard enough to be a rookie in this league when this is your only job. He has two jobs, so that's more challenging, but that's something that people like Joe, who have been in the Naval Academy, have experience with -- time management, multi-tasking, doing different things and handling different levels of responsibility physically, mentally and emotionally."
As part of his work at the Naval Preparatory Academy, Cardona said his work responsibilities are varied like any staff officer.
"A lot of it is mentorship to students that are in the same situation I was in five years ago as far as going through the Naval Academy Prep School and preparing for life at the Naval Academy," he said.
Belichick has deep roots at the Naval Academy, where his late father, Steve, was a longtime coach and associate professor in the department of physical education; a collection of Steve Belichick's historic football books is preserved there in the Belichick library.
It is easy to sense that Cardona's presence on the team means a lot to Belichick, who had personally met with him before the draft during the Patriots' April trip to the White House to be honored for their Super Bowl championship.
One behind-the-scenes moment of note this season came after the Patriots' 30-23 victory over the New York Jets when Secretary of the Navy Ray Mabus joined the team in the locker room. Mabus had been in town as a guest of owner Robert Kraft, and when Belichick introduced him to the team after the comeback victory, he naturally made reference to Cardona's presence as well.
"For me, it was something really special," Cardona said. "Realistically, he's a call away from the president. That's a great honor to meet anyone of that stature any time."
A native of El Cajon, California, who was a star football and lacrosse player in high school, Cardona's standing as an active member of the Navy has been reflected in how he dressed in his Navy Whites before and after games. Just as the Navy has, he has since switched to Service Dress Blues.
"It's a comfort factor for me," he said. "It's what we showed up to games in at the Naval Academy. It's sticking with what works."
For the two teammates he's closest with, Gostkowski and Allen, it's been a perspective-filled experience working together.
"You can tell he's just so disciplined, coming from the Naval Academy; he's come in and worked hard, kept his head down, and he's humble and has a lot of respect for everyone and how they do it," Gostowski said. "He has his job on the side serving our country, which is some of the highest respect you can have. It's the kind of thing I've never been around and it's been cool to be a part of."
Said Allen, "From the get-go come in and kind of had a put-head-down-and-work mentality, which is probably from his background and schooling the last 4-5 years. He's a hard worker. He came into this environment, a small niche with me and Steve, and he's worked well. He's quiet, he puts the time in, and that's where trust is built between us three."
As for the technical work of snapping, Belichick has noticed a steady growth from Cardona, saying, "He's improved a considerable amount since we first started working with him in the spring."
Gostkowski said he sees it, too.
"Joe's doing great," he said. "A lot more goes into it than people think. For every one snap Joe does in a game it is probably hundreds of snaps in practice. He's done a good job, and he can take coaching very well. He just says 'yes sir' and does his job."
Cardona said the biggest adjustment in transitioning to the NFL has been adapting to the speed of the game and blocking schemes. This month, his work at both jobs, which is also reflected on his Twitter profile, has intersected in a sense as part of the NFL's "Salute to Service" campaign.
"I think it's a special thing that's done for the men and women in uniform," he said. "I just feel strongly about service and those who have taken the oath to protect and serve. There are a lot of people from the Naval Academy doing a lot of great things. To be representing, and doing whatever I can on this stage, I feel very lucky to have the background I have."
As for the significance of Veterans Day, Cardona said, "To me, every day is Veterans Day. Every day is Memorial Day. Every day is the Fourth of July. There is not a difference between those days and any other days of the year, but obviously, it's a special day to remember those who have served our country and fought for it. That means a lot to me."