The mystery donor whose $1 million contribution set off a furor over secrecy in politics has been identified as a longtime supporter of Republican presidential candidate Mitt Romney.

Edward Conard, a former executive at Bain Capital, a private equity firm that Romney helped found, gave the contribution to a pro-Romney super-PAC called Restore Our Future through a shell corporation, W Spann LLC.

Conard said in a statement to Politico that he made the anonymous donation “after consulting prominent legal counsel regarding the transaction, and based on my understanding that the contribution would comply with applicable laws.” Conard said he has asked the group to amend its disclosure filings to list him as the donor.

The contribution attracted public attention recently after NBC News noted the unusual circumstances surrounding W Spann, which appeared to have no other purpose than making the PAC contribution before dissolving in July. The arrangement underscored the increasing ways in which wealthy donors and corporations are able to cloak their political activities.

Election watchdog groups argued that W Spann may have violated contribution rules banning the use of straw donors to evade disclosure. The Campaign Legal Center and Democracy 21 filed complaints about the case Friday with the Federal Election Commission and the Justice Department.

Paul S. Ryan, a lawyer with the Campaign Legal Center, said official inquiries should move ahead despite Conard’s decision to come forward.

“The FEC and DOJ will still have to determine whether the actions to date violated federal law and, if so, pursue appropriate penalties to deter such conduct in the future,” he said in a statement Saturday.

Restore Our Future, which as a super-PAC can raise and spend unlimited amounts of money, reported $12 million in donations for the first half of the year to help fund efforts supporting Romney. The group was founded by three former Romney aides, and Romney spoke to a private dinner for Restore Our Future donors last month.

“We’re glad Mr. Conard has chosen to come forward, putting an end to this supposed controversy,” said Brittany Gross, a Restore Our Future spokeswoman.

Conard is a longtime Romney supporter who gave $100,000 to the former Massachusetts governor’s network of state political action committees, which helped fund his political activities before his official 2012 campaign.