Obama was welcomed in Las Vegas Friday with cries of "Si se puede" (Yes We Can).
He had earlier, resorted to unilateral executive action to fix America's "broken" immigration system.
"We're going to keep on working with the members of the Congress to make permanent reform a reality," Obama told an enthusiastic crowd at the Del Sol high school in Las Vegas.
"But until that day comes, there are actions that I have the legal authority to take, that will help (to) make our immigration system more fair and more just, and this morning I began to take some of those actions," the president said.
The choice of Del Sol as the venue for his first public appearance after announcing the executive orders was symbolic, as Obama had delivered a major speech on immigration at the mainly Hispanic school in 2013.
Obama stressed that he felt compelled to act alone after Republican House of Representatives Speaker John Boehner refused to allow a vote in the lower chamber on the bipartisan immigration reform bill that the Senate passed in June 2013.
"I told John Boehner, I'll wash your car, I'll walk your dog; whatever you need to do, just call the bill," Obama quipped.
"We're not a nation that kicks out strivers and dreamers who want to earn their piece of the American dream. We're a nation that finds a way to welcome them," the president said.
"We make them earn it, but we welcome them as fellow human beings (and) fellow children of God, and we harness their talents to make the future brighter for everybody," he said.
The largest group of likely beneficiaries of Obama's plan are undocumented migrants without criminal records who have lived in the US since prior to Jan 1, 2010, and are the parents of children who are US citizens, or legal permanent residents.
Besides being protected from deportation for three years, those individuals will receive work permits.
While 5.9 million Mexicans make up over half of an estimated 11.2 million unauthorised immigrants in the US, India is the fourth top source country with 450,000 people living in the US without papers, according to a new Pew Research Centre report.
About 8.1 million unauthorised immigrants make up 5.1 percent of the US labour force, the report said. Many of them are engaged in menial low paying jobs that Americans don't want to do.
To qualify, undocumented immigrants will have to prove that their children were born before the president's announcement and that they have lived in the country for at least five years.
Applicants must also submit to extensive background checks and pay fees.
Obama also ordered the department of homeland security to focus immigration enforcement activity on national security threats, serious criminals and recent border crossers, defined as undocumented immigrants who entered the country after Jan 1, 2014.