Snyder said the chance to cover nearly half of the state's uninsured is "huge," adding that he is comfortable the health care system can handle the extra caseload.
The federal health care law gives states the option to accept the expansion, refuse it or postpone a decision. But there are benefits for states that choose to expand Medicaid now: The U.S. government will pick up the entire cost in the first three years and 90 percent over the long haul.
Snyder is expected to run into resistance from Republican lawmakers opposed to the health law.
Rep. Joe Haveman, a Holland Republican who chairs the House Appropriations Committee, said his proposal deserves a closer look, but Republicans have questions.
"The federal government has a long history of promising support for long-term government programs and then coming up well short when the time comes to honor their commitment," Haveman said in a written statement. "We are going to do what's best for the people we serve and do our homework on this proposal before committing one way or the other. Michigan residents deserve that."
Ohio's John Kasich earlier this week reiterated his opposition to what he called "Obamacare" and the requirement that people have health insurance, but said Medicaid expansion makes sense for Ohio. Pennsylvania's Tom Corbett said he will not pursue an expansion, at least for now, echoing complaints of other GOP governors about the cost, inflexibility and inefficiency of Medicaid.
Snyder said Medicaid expansion would save the state $200 million a year initially because more people who now receive mental health services and medical care from state-funded programs would instead be covered with federal money. He called for setting aside $100 million a year of those savings so Michigan can pay 10 percent of the cost for new enrollees down the line. He said the expansion would effectively cost Michigan nothing until 2035.