If the winner of a Democratic primary next week defeats Walker in the June 5 recall election, Walker will become only the third governor in American history to be recalled.
But while Christie said he spoke to Walker regularly during last year's controversy, the New Jersey governor mentioned the word union only once in two appearances with Walker on Tuesday.
Instead, Christie listed his own fiscal accomplishments in New Jersey, promised an income-tax cut in the state by July 1, and spoke broadly about "special interests that have owned these state capitals for too long."
Christie frequently travels to GOP events around the country - he'll be in Kentucky in two weeks - but he balances his rhetoric so as to appeal to conservative audiences while preserving his high popularity in moderate New Jersey.
Christie's trips sometimes consist of only closed-door fund-raisers. Tuesday's trip, paid for by the Walker campaign, included one private fund-raiser but also two public appearances with Walker and his wife - at the rally outside Milwaukee and a luncheon in Green Bay ($100 a plate, $1,000 for a photo).
The men drove past several union protesters on the way into the luncheon.
Walker called Christie "courage personified" for fighting the budget-cutting cause in "arguably one of the toughest places in the country."
Walker is shattering state campaign fund-raising records (more than $13 million raised in three months), drawing money from some of the same national conservative financiers who supported GOP presidential candidates. His recall election is seen as a possible preview of what to expect in the presidential race - Wisconsin went for President Obama in 2008 before dumping Democratic state leadership two years later.
"For the next five weeks, Wisconsin is going to be the center of the American political universe," Christie told a few hundred Walker supporters in the garage of a landscaping company in Oak Creek, south of Milwaukee.
After Christie's speech, 68-year-old Del Ellefson - wearing a "Proud to be a Tea Party Terrorist" T-shirt - told a reporter: "Love that man."
Others in the crowd, cellphone cameras aloft, echoed that sentiment. Having only seen Christie on Fox News, they said this was their first time seeing him live. One man yelled: "VP!"
Like Walker, Christie made a name for himself looking to public unions for budget savings. Christie signed laws to limit contractual increases awarded by arbitrators, cap tax increases at 2 percent, and cut benefits for hundreds of thousands of workers and retirees.
Last spring New Jersey union leaders called this last measure a "Wisconsin response" because it set certain elements of employee contracts by law, instead of through negotiation. Several large protests were staged outside the Statehouse.
At the time Christie said he was not replicating what was happening in Wisconsin, despite what the "Democratic party and the liberals in the media" may try to argue. He declared his "love" for collective bargaining.
Notably, unlike Walker, Christie allied with Democratic leaders in the Legislature to get these measures through. And in January, the Christie administration signed a four-year contract with the third-largest negotiating group of public employees. A tentative agreement is now on the table with another large union, according to the governor's office.
"I've supported many candidates over time whom I don't agree with everything they've done," Christie said at a news conference Monday when asked about Walker's policies.
"It's obviously very different. . . . The fact that I'll go out and campaign and raise some money for Scott Walker, who I think is by far the best candidate for the governorship of Wisconsin, doesn't change what my policies are every day on the ground here."
Back home though, liberals did not see daylight between Walker and Christie.
"They've both attacked the rights of middle-class workers, and they've both passed budgets with billions in devastating cuts to the services on which strong job creation relies," said a statement from the New Jersey Working Families Alliance.
State Sen. Barbara Buono (D., Middlesex), a likely 2013 gubernatorial candidate who voted against Christie's health-benefits and pension law, also released a statement about Christie's trip: "Our governor seems more concerned with one man's job in Wisconsin than the legions of unemployed constituents at home."
Despite the rosy outlook from the governors Tuesday, neither state has experienced a full economic recovery.
New Jersey's unemployment rate is 9 percent, higher than the national average, and Wisconsin is the only state in the nation with "statistically significant" job losses from March 2011 to March 2012, according to the U.S. Bureau of Labor Statistics.
In a sign that the Wisconsin issue is a prelude to the November election, the Koch brothers - billionaire industrialists who have come to personify union-busting for the left - have donated plentifully to Walker. In February, David Koch told the Palm Beach (Fla.) Post: "If the unions win the recall, there will be no stopping union power."
In his speeches Tuesday, Christie mixed some of his standard talking points (the cast of Jersey Shore is from New York, not New Jersey) with some new laugh lines.
Of most interest, but least import? Christie's 16-year-old daughter, Sarah, apparently has a crush on Walker's teenage sons.
Contact Matt Katz at 609-217- 8355, firstname.lastname@example.org, or follow on Twitter @mattkatz00. Read his blog, "Christie Chronicles," at www.philly.com/ christiechronicles.