Marquette, Michigan (CNN) -- U.S. Rep. Bart Stupak, the anti-abortion Michigan Democrat criticized for his role in backing President Obama's health care plan, said Friday he won't seek re-election.
Stupak told reporters his service to Michigan has been "one of the great honors of my life" and that it's "time to begin a new and exciting chapter" in his life.
He said his announcement allows potential candidates to organize campaigns and that he's "committed to helping the Democrats retain this seat."
Stupak said he is departing after health care reform became law.
"We finally accomplished what I set out to do 18 years ago. We passed comprehensive national health care reform," he said. "Throughout the past year, I've worked alongside my colleagues to achieve health care reform, and I'm proud to have helped bring it across the finish line."
Stupak said he's considered retiring from Congress before but there were pressing issues, such as the Iraq war, efforts to bring Democrats into the majority and work with a new president on health care reform.
"I thank President Obama and Speaker [Nancy] Pelosi for their leadership to put us across the line as we finally have health care a reality in this country," he said.
He added that "now it's time to spend a little more time" with his family.
"It's a good time for me to make the decision. We have a large majority in the House, a large majority in the Senate, a Democratic president, now's the time to go, " he said. "So am I worried about it? No, I've seen the Republican field, and obviously I'm not impressed. It's really, in my estimation, it's one of the weakest fields I've seen in some time. I think there are many Democrats who can hold my seat. "
Stupak has faced opposition from both the right and the left for his eleventh-hour deal with the White House to support the administration's health care legislation.
The lawmaker has said he struck the deal because he was convinced that the measure bans federal funding for abortion.
Stupak first informed Democratic leaders last week that he was considering retiring, and he received calls from Obama, Pelosi and others urging him to run again.
Democratic sources in Washington and Michigan said they fear the retirement of Stupak, a nine-term, popular Democrat in the sprawling conservative 1st Congressional District, likely would mean losing his seat to a Republican in the fall.
Tea Party Express spokesman Levi Russell said the group has been the only one bringing "major national attention" to Stupak and believes the development reflects his movement's clout.
Russell said Stupak had been aware that the Express has been "barnstorming" the Michigan's Upper Peninsula.