Biden, who appeared with Corzine the night he accepted the Democratic Party's nomination for a second term in June, was with the governor again on Wednesday at the state AFL-CIO legislative convention in Atlantic City.
"We made a decision immediately, early and without any hesitation that we would do anything we needed to do, anything he wanted us to do, we would do to help him be re-elected," Biden said. "It's critically important he be re-elected."
Biden, who spoke for about 35 minutes, urged union members to campaign hard for Corzine, saying his own political career would not have been possible without their support.
"Let me start by saying thank you for what you've done for me, thank you for what you did for our ticket this last election, thank you for all you continue to do for the people of New Jersey and what labor does for this great country," Biden said to cheers.
He credited Corzine with helping craft the national economic stimulus plan and said the governor - not GOP challenger Chris Christie - will "put New Jersey in a position where the moms and dads in the state four years from now will be able to look their kids in the eye and say, 'honey, it's going to be all right."'
"I know Jon Corzine, I've served with Jon Corzine. We've become close friends," Biden said. "He's tough, he's smart, he's honest, he knows more about the economy than 95 percent of the people of either political party. ... But the thing that is most essential now is to have someone in a position of power who understands the pain of the American people."
Corzine introduced Biden as "an American hero."
The governor said he'd focus in a second term on creating good-paying, sustainable jobs as the economy rebounds.
"Just as you are standing with me for the next 27 days," Corzine said in reference to the number of days before the election, "I'll be standing with you from 8:01 on Nov. 3 for the next four years. We have a lot of work ahead."
Corzine, who is locked in a three-way race with Christie and independent Chris Daggett, also has support from teachers and police and fire unions. Christie has pledged to lay off workers and reform the pension system if elected.
Union support could be a key to the election. AFL-CIO New Jersey President Charles Wowkenech said 1,200 or more campaign volunteers will be knocking on doors for Corzine every weekend until the election.
Biden's primary night trip to West Orange was nearly skirted because Corzine was locked in a tense labor negotiation and union members threatened to picket. Biden was unlikely to cross a picket line.
A deal was hastily struck between the administration and the unions, whose contract Corzine was renegotiating because of the recession.
Corzine trailed Christie in the early stages of the campaign, but recent polls show the governor has closed the gap.