He had to decide quickly whether to drop out or press on with a court battle. Thursday's ruling came with less than seven weeks before the Nov. 8 election and just as ballots are to be printed and sent out, first to voters overseas, then to others.
Lewis said he would still be involved in Democratic campaigns and charity work - and encouraging people to vote.
"Service does not need a title," he said Friday.
His withdrawal caps a week of suspense in his stop-and-go challenge to Republican incumbent Dawn Addiego for a seat representing the heavily Republican 8th Legislative District in the outer ring of southern New Jersey's Philadelphia suburbs.
The Democrat's campaign, begun in April, has been heavy on legal proceedings and light on political debate - though Lewis did knock on plenty of voters' doors.
Lewis, 50, grew up in southern New Jersey but settled in California. He bought homes in New Jersey in 2005 and 2007 and became a volunteer track coach at his alma mater, Willingboro High School, in 2007. But he continued to vote in California until 2009 and didn't register to vote in New Jersey until he started his campaign.
New Jersey Secretary of State Kim Guadagno, a Republican who is also the state's elected lieutenant governor, deemed him ineligible. She was backed up by Burlington County Republicans who intervened in the case.
Lewis's lawyer argued in court after court that Lewis is a known figure and not a carpetbagger - so there was no reason to bar him from running.
He persuaded the 3rd Circuit panel to keep Lewis on the ballot for the June primary, but it didn't work to keep him there for the general election.
At a rambling news conference Friday, Lewis focused on what he's accomplished in life and seemed Zen about his political fate. When a reporter's cellphone rang, Lewis answered: The reporter, he told the caller, was covering something, but he'd call back later.
Lewis, who wore a shirt with the Nike logo on it, said he wasn't angry about the court ruling.
"They made their choice, we move on, that's where I am," Lewis said.
He said he didn't spend Thursday fretting about what to do in response to the court ruling. His big concern, he said, was finishing building a shed before it began raining.
He said he won't run for statewide office or Congress but said he could possibly run for the Legislature in the future - a job that he believes would let him continue sponsoring Nike, being an ambassador for the United Nations and other nonpolitical activities he enjoys.
"In terms of 2013, I mean, I have no idea what I'll be doing in 2013," Lewis said. "If you had asked me April 4 if I would be running April 11, I would have said, `What are you kidding me?"'
"I let the spirit move me," he said.
He said he may write a book about his five-month campaign. The only thing he's ruled out for the future is resuming a project he embarked on with Republican Gov. Chris Christie before he entered the race: becoming a New Jersey fitness ambassador.
The fitness program led to a partisan spat early in his campaign. Lewis said Christie's staff threatened to scuttle the program if Lewis ran. The administration dismissed Lewis' interpretation as a misunderstanding but acknowledged that the program was dead.
"I'd like to work with people whom I can trust," Lewis said Friday with a wink.
Unless there's a change quickly, the 8th District ballots will be printed without a Democratic candidate.
Joe Andl, the chairman of the Burlington County Democratic Committee, said he expects to determine by the end of the weekend whether the party will try to replace Lewis on the ballot.
Jacqueline Jennings, the vice-chairwoman of the group, said it would have been inappropriate to line up a backup candidate in case Lewis was ousted.
"It's the people of New Jersey who lost," she said. "Not Carl Lewis."