"We need Congress to act on a comprehensive approach that finally deals with the 11 million undocumented immigrants," Obama said at a high school in Las Vegas.
After years on the back burner, immigration reform has suddenly looked possible as Republicans, chastened by Latino voters who rejected them in the November election, look more kindly on an immigration overhaul.
Obama was speaking a day after a group of influential Senate Democrats and Republicans laid out a broad plan of their own that is similar to White House immigration proposals.
He said that if Congress is unable to act in a timely fashion, he will propose immigration legislation of his own and demand lawmakers vote on it.
Immigration reform could give Obama a landmark second-term legislative achievement, but the White House is mindful that success on such a divisive issue will require a delicate balancing act.
Obama's challenge is to spur progress toward actual legislation guided by the senators' immigration plan without alienating his fiercest Republican opponents, who might oppose anything with the Democratic president's name on it.
Foreshadowing what could be a critical area of disagreement with Republicans, Obama stopped short of backing the Senate group's requirement that providing a path to citizenship be contingent on first doing more to secure the nation's borders - a concession that was made to appeal to conservatives.
Another point of contention is expected to be whether same-sex couples are granted the same benefits as heterosexual couples under immigration reform - something the White House says Obama will insist upon but which the Senate group did not deal with.