"We've been talking for over a month, kind of since the New England game," Harris told ESPN.com. "I'm just ecstatic to have it done, really focus on straight football right now. But what a year, my wife and I having a baby, this, coming back from my surgery, I'm glad [the contract] is something that's done now."
Harris, who is considered among the elite cornerbacks by personnel executives around the league, was one of several high-profile Broncos poised for unrestricted free agency at the end of this season.
Harris will receive a $10 million signing bonus -- half upon signing the deal and half in March -- and the contract includes $24 million in guaranteed money.
"It feels great, but I still have to go out and prove it every day," he said. "I've still got a lot to prove, a lot of things I want to accomplish with this team, being a leader, helping this team accomplish big things.
Added Broncos executive vice president/general manager John Elway in a statement Friday: "It's a priority for us to develop and reward our own players as we continue assembling the best possible team. Whether it's on the field or in the community, we are proud to have Chris representing the Broncos for many years to come."
Champ Bailey had called the impending financial shot.
On the day last month when Bailey formally announced his retirement from the NFL, he said Harris was "playing better than anybody right now. ... Chris is playing the best of any player at his position in the league."
Then Bailey added, "I hope [the Broncos] pay him like it. I think they will. Knowing John Elway, how he goes about it, I think they will."
Last week, Harris echoed his thoughts from earlier this season that "it seems like people maybe rank you on the contract or whatever. ... I just want to keep working, be the best corner out there and everything will take care of itself. I've always felt like if I get the chance to show people what I can do, they'll see it and acknowledge it."
Harris, who had ACL surgery in February, has 45 tackles this season and is tied for the team lead in interceptions with three despite rarely being tested by opposing quarterbacks. Singled up on Kansas City Chiefs wide receiver Dwayne Bowe for virtually every snap in a 29-16 Broncos win, Harris held him to two catches for 18 yards in the game.
The deal also means that in the Broncos' secondary: Aqib Talib, who signed a six-year, $57 million deal this past offseason, is signed through the 2019 season; safety T.J. Ward (four years, $22.5 million in March) is signed through '17; and rookie cornerback Bradley Roby is signed through '17.
Harris was signed as an undrafted rookie in 2011 for a $2,000 signing bonus. He made the team's 53-man roster largely as a special teams standout at that point but has since evolved into one of the league's most versatile defensive backs.
Harris is able to line up in the outside positions at cornerback on either side of the formation as well as in the slot on either side of the formation.
"Chris just practices so hard, plays so hard," defensive coordinator Jack Del Rio said. "He competes every day, in practice, in games, every snap, even when he rehabbed his knee, and those are the kinds of guys we want in our defense."