Acting Massachusetts governor Jane Swift withdrew her name from the governor's race Tuesday after the head of the Salt Lake City Olympics Committee announced his intention to challenge her in the Sept. 17 Republican primary.

"I believe that this is in the best interest of our state as it will allow the Republican Party's best chances of holding the governor's office in November," Swift said, fighting back tears at a noon news conference at the Statehouse.

A wealthy businessman from a long line of political veterans, Mitt Romney announced Tuesday afternoon that he will not make a formal announcement "in front of a band with confetti and a lot of cheering spectators" because he wants it to be Gov. Swift's day.

"I want to note, however, that lest there be any doubt, I'm in.  The bumper stickers have been printed.  The Web site is going up tomorrow morning.  The campaign papers are filed today," Romney said.

A Boston Herald poll from last week indicated Romney would soundly trounce Swift if the election were held today. Of 401 likely GOP voters, 75 percent favored Romney to 12 percent for Swift.

Swift, 37, became the first governor in history to have a child while in office. In fact, she had twins and there was a tremendous outcry at the time that she would not be able to fulfill her duties as the highest ranking official in the commonwealth of Massachusetts.

On Tuesday, Swift that she decided not to take on the task of being a mother, running for election and governing the state during a budget crunch. Swift has three young daughters, including twins born in May.

"Having said early on the time with family was non-negotiable, something had to give," she said.

She will not resign her seat.

Romney, whose father was governor of Michigan, challenged Sen. Ted Kennedy in 1994, spending millions of his own money and breaking records for money spent on a Senate race. He lost against Kennedy, but the moderate Republican could break new records in spending for a gubernatorial race. 

Five Democrats are running for governor: Senate president Thomas Birmingham, former Labor Secretary Robert Reich, state Treasurer Shannon O'Brien, former state Sen. Warren Tolman and Steve Grossman, a former national Democratic Committee chairman.

The Associated Press contributed to this report.