The contract for the cornerback from Rutgers is worth $13.2 million with $7.825 million guaranteed, according to his agent, Andy Simms.
McCourty, a cornerback from Rutgers, was the 27th overall selection in the draft. He was the last of the Patriots' 12 draft choices without a contract. McCourty was eager to report by Wednesday, when veterans were due at 7 a.m. Simms said McCourty signed his contract at about 7 a.m.
"We worked pretty late [Tuesday] to get to this point," Simms said. "We know what's important in New England and that's to get to camp on time."
McCourty is the second first-round draft choice to agree to a contract; Cowboys receiver Dez Bryant (24th overall) is the other.
In selecting McCourty, Patriots coach Bill Belichick cited his four-down impact, meaning that he could contribute both on defense and special teams.
"He's fast, he's tough. He's a good four-down football player -- first, second, third and fourth down," Belichick said on draft day. "In the kicking game, he's certainly one of the top guys in the draft in that area."
In addition to contributing on special teams, McCourty is projected to compete for a starting job at left cornerback with 2009 second-round draft choice Darius Butler.
The negotiations took place with the possibility of a lockout in 2011 if management and the players' union can't agree on a new collective bargaining agreement.
"The pending labor situation is something we had to consider. We worked with the Patriots on some of the issues," Simms said.
Mike Reiss covers the Patriots for ESPNBoston.com. Follow him on Twitter. Information from The Associated Press was used in this report.