Financial terms of the deal, which runs through 2018, were not disclosed but it was reported to be worth $120 million with close to $50 million guaranteed, according to ESPN.com.
The numbers are staggering, but Fitzgerald stressed that it wasn't all about the money.
Sitting next to Cardinals president Michael Bidwill at a press conference, the wide receiver said the most important legacy he hopes to leave is on the field.
"I'm really uncomfortable being up here talking about this type of thing," Fitzgerald said about the contract.
Fitzgerald, 27, signed a four-year, $40 million extension in March 2008 that was meant to alleviate the salary cap crunch his previous contract was causing the team, a situation that led to trade rumors.
He has been one of the premier wide receivers in the NFL since the Cardinals selected him No. 3 overall in the 2004 draft -- a big target at 6-foot-3 and 218 pounds who has caught at least 90 passes in five of his seven seasons with Arizona.
Last year, Fitzgerald had 90 receptions for 1,137 yards and six touchdowns. He caught a career-high 103 balls in 2005 and had a career-best 1,431 yards receiving in 2008. His highest TD total was 13, in 2009.
Fitzgerald, who has missed just four of a possible 112 games, has 613 career receptions for 8,204 yards and 65 touchdowns.
"I'm going to continue to be aggressive and make this team better," said Fitgerald, "and I'm confident that it will happen."
Bidwill called Fitzgerald one of the most dynamic players in the NFL and said they wanted to get a deal done before the regular season started.
"This is a day that I think all of us have been looking forward to," he said.
Congratulations poured in on social media.
Titans running back Chris Johnson, who is holding out for a big contract of his own, tweeted his congratulations. Fitgerald replied: "thanks CJ you up next my guy." He also tweeted thanks to Phoenix Suns guard Steve Nash and Pittsburgh Steelers defensive back Ryan Clark.