A consensus four star linebacker from El Cerrito High School just outside the San Francisco Bay Area, Calhoun was rated as the top high school defensive player and most intense defensive player in Arizona State's 2014 recruiting class.
A one-time USC commit, Calhoun pledged to the Sun Devils in late October following a visit and made things official when he signed his paperwork just a month later to become the team's only early enrollee from the high school ranks, joining junior college transfer Edmond Boateng.
The freshman arrived on campus in early January along with the rest of the student body following the holiday break and has hit the ground running ever since.
On Tuesday, he and his Sun Devil teammates returned to the Kajikawa practice field for the first time since late December for the start of spring camp as Calhoun got his first taste of college football.
"Everything is fast," he said after practice. "The pace is way different than in high school. I was just trying to listen to everybody. Listen to all the players, see how they're doing things, follow their footsteps, and just go with the flow."
While Arizona State is coming off its first 10 win season since 2009, the Sun Devils are faced with having to replace nine starters on defense, including two linebackers at the SPUR and WILL positions. It was that opportunity to compete for an early starting position, even as a young freshman, that motivated Calhoun to get down to Tempe before the other 24 commits in this year's recruiting class arrive during the summer.
Calhoun credits redshirt freshman Marcus Ball with helping him get acclimated to his new surroundings and getting him up to speed on the fast-paced Sun Devil defense before the start of camp.
"When I came in, he just taught me everything," said Calhoun. "He was telling me how the coaches work, how the players work, and what to expect. He just took me under his wing. And then, just a lot of the players too, like Salamo."
Rated as the 28th overall prospect in the west by Scout and the 13th best outside linebacker, Calhoun spent his first full practice backing up Laiu Moeakiola at SPUR, but also figures to see time at the WILL position, according to Head Coach Todd Graham.
"That guy's impressive," said the coach. "He can run, move, cover - he's going to be special. We're excited about him and we threw him in there today. He showed up and had a great spirit about him. He ran on and off the field the way we want to and that's the key. It's how you do the little things that makes the biggest difference. But I was very impressed with DJ."
"I love the SPUR position," added Calhoun "because you're basically playing free safety in a way, so at SPUR you make big plays. You just have to be fast and I think that fits me very well."
Aside from the speed of the game, one of the biggest challenges Calhoun pointed out following his first full practice session with his new team was the size of some of the other players he was competing against.
"I'd say size, but that never stops me because I'm not scared of anybody," he remarked. "As a linebacker, you shouldn't be scared. But just looking at everybody, there's a size difference. It's kind of intimidating in a way because you'll be looking at linemen who are, like, 6-6 and I'm 5-11. But I'm going to work my way up, lift weights, and get bigger."
Part of that plan to get bigger requires spending time with Sun Devil Strength and Conditioning Coach Shawn Griswold, which is something Calhoun has done plenty of since arriving January. In just two months, the freshman says he's bulked up 16 pounds from 189 to 205 pounds, and still has more room to grow.
Over that same time, Calhoun has also created a bit of a reputation for himself on campus.
Defensive Coordinator Paul Randolph recently told DevilsDigest that he sees a combination of former Arizona State linebackers Brandon Magee and Chris Young in Calhoun while the former gave the frosh his the seal of approval on Twitter, saying he thinks Calhoun will be the next great linebacker for the Sun Devils.
"It means a lot because he was a big time player," he commented. "Everybody's compared me to him and Chris Young. I've actually been looking at their highlights on YouTube and just looking at how they play. They were small too but they got bigger by the time they got to their senior year, so I've just been looking at that and getting ready to play.
"But I don't even really pay attention to the hype. I'm just a very humble player. Just talking with Coach Graham, he said, 'You've just got to be humble about yourself. Just look past all that and do what you've got to do."
Of course, Magee and Young aren't the only two former Sun Devils that Calhoun is taking after. He also proudly wears the number four, which was most recently worn by safety Alden Darby, one of the most instrumental leaders of the Arizona State defense over the last four years.
"He was the host for my official visit," said Calhoun. "He was one of the guys who talked me into coming here and love him, so it's cool."
Another player who had a great impact on Calhoun changing his commitment from the Trojans to the Sun Devils was incoming freshman Manny Wilkins. As another Bay Area standout, Wilkins and Calhoun hit it off during the recruiting process, first at camps and then once again when they both tripped to Arizona State in late October.
"When we came here, I was on my official. Me and Jalen Harvey and Manny was on his unofficial," he said. "We were all in the academic room, just choppin' it up and he was telling us, 'We could build something here. We've got 25 commits and our team is young. We've got some freshmen in place right now so we can definitely do something special together.'
"That's my guy. That's one guy that I can say is going to take over this program, especially since he has a year to learn from (Taylor) Kelly. And Kelly's a real good leader, but Manny, he's got the leadership and everything at a young age."
With day one in the books for Calhoun, the plan going forward is just to get better each day and position himself to contend for a starting job come the fall.
"After this, I'm trying to go with some of the guys and look at the film of practice so I can pick up on some of the details and everything," he said. "I just want to get out here and show everybody what I can do and just put on for everybody back home."