Charles, who spent nine years with the Chiefs, spoke to reporters Monday about his past.
"I'm just happy to be a Bronco," Charles told reporters after Broncos OTAs. "The past is the past. If I was still a Chief, I would be there now. I'm here now."
Charles is the Chiefs' all-time leading rusher.
"I was fired. Hey, it's a business," Charles told reporters. "I'm excited to be a Bronco. I've wanted to be a Bronco since I was a little kid when I looked up to John Elway and saw how he carries his team and [Pro Football Hall of Fame Inductee RB] Terrell Davis at running back. That inspired me as a little kid. I just like the way the organization was back then."
Charles drew ire from fans when former Green Bay Packers tight end Jermichael Finley posted a photo on social media showing himself posing with a group of guys including Charles. Charles was wearing a throwback John Elway jersey in the photo. He explained himself in his Monday press conference.
"I've been an Elway fan," Charles told reporters. "You go back on my Instagram, you'll see that way before. That was a 'throwback picture.' That was in college. I'm just excited to be a Bronco right now, so I'm not really caring about what people think. I was fired."
Finley and Charles were teammates for two seasons with the Texas Longhorns. Charles was born in Texas and went to high school in the Lone Star State.
Despite entering a backfield already containing a Pro Bowler in C.J. Anderson and talented second year back Devontae Booker, Charles says that he should be "the man."
"Why would I not think I'm going to be the man," he told reporters. "You think I just want to come in here and be like-that's never been me in my whole life. My whole life, I've always felt like I'm going to be the man. That is what I want to come up in here. If I'm not going to be the man, why am I here? I should be at home sitting on the coach."
Charles also said he wants to come in and compete and make everybody better. He has a desire to "turn Booker into a Pro Bowl running back" and make Anderson an All-Pro.
"I want to show up and compete with my teammates and show them that I am good and that I am still at the top of my career," he told reporters.
Charles, 30, hasn't played more than five games in a season since 2014 because of various injuries. He averaged a career-worst 3.3 yards per carry in 2016.
He hasn't been fully cleared for OTAs but is participating in light drills. Charles has torn both ACLs and had two knee surgeries since November.
"He's made great progress as far as his rehab," Broncos coach Vance Joseph told reporters. "He came here, his quad was really weak. Now, it's gotten stronger. He's running hills. He's with [assistant head coach/running backs] Eric [Studesville] with a couple individual drills, so he's getting closer. His timeframe won't change; he'll still be ready for training camp for us."
In May, 9 News Denver reported that he was a 50-50 shot to make the Broncos' roster. Charles signed a one-year contract with the team in early May, but the deal is heavy in incentives. Charles can cash in for another $2.75 million, mostly related to if he is active on Sundays.
For now, Charles' chances of making the roster will increase when he actually gets into training camp. If he does make the cut, expect him to play a change-of-pace role, backing up Anderson.