"I'm proud of him for doing it and I thanked him for doing it," he said of Bush during a "Cafe con Clinton" breakfast speech to the annual conference of the National Council of La Raza, the nation's largest Hispanic civil rights advocacy group.
Clinton said Bush's roots in Texas — which has one of the nation's largest Hispanic populations — have helped him view immigrants as people rather than statistics.
"It's hard to demonize people if you know them," he said.
But Clinton also argued that the nation's government is controlled by Republican ideological hard-liners who want to use immigration to divide Americans and distract them from issues such as the war in Iraq and the health care crisis.
Instead of equal opportunity, they support a "financial elite" because they favor "concentrated wealth and power," Clinton said.
"They believe in a government that is secret, unaccountable and that maximizes its own power," he said. "They really believe the world works better if they run it and we keep our mouths shut."
Clinton supported an immigration reform measure passed by the Senate that would provide a way for many of the estimated 12 million foreigners living in the country illegally to become citizens. A House-approved bill would make illegal immigrants felons and build 700 miles of border walls. House and Senate negotiators so far have not been able to work out a compromise.
Bush has said he wants to enforce the borders so fewer people sneak across but also provide a way for those already in the United States to become legal. He has praised Hispanic immigrants as hardworking and family oriented. Clinton used similar language in his own speech.
The message played well with La Raza, which opposes the House bill and whose current president, Janet Murguia, was an assistant in the Clinton White House.
Before Clinton's speech, Los Angeles Mayor Antonio Villaraigosa noted a string of rallies over the immigration issue, including one in March that sent 500,000 people into the streets of Los Angeles and garnered international attention.
"You literally reshaped the political landscape of our nation... we can still see a movement blooming before our very eyes," he said.
Both Democrats and Republicans have been looking for ways to court Hispanics, whose fast-growing population gives them the potential to become an enormous voting force. Bush's top political adviser, Karl Rove, was scheduled to address the convention on Tuesday.