The former president approached Sestak last summer when he began his challenge to Sen. Arlen Specter, who had changed parties -- from Republican to Democratic -- and had President Obama's backing, the White House said in a report Friday in The Washington Post.
Chief of Staff Rahm Emanuel had asked Clinton to approach Sestak, who defeated Specter this month, the report said.
The report said allegations of improper conduct "lack a basis in the law" and concluded talks about Sestak's options in the Senate campaign were proper.
"The Democratic party leadership had a legitimate interest in averting a divisive primary fight and a similarly legitimate concern about the congressman vacating his seat in the House," the report said. "There have been numerous, reported instances in the past when prior administrations -- both Democratic and Republican, and motivated by the same goals -- discussed alternative paths to service. ... Such discussions are fully consistent with the relevant law and ethical requirements."
Sestak refused to discuss the report's findings, telling reporters Friday, "I'll have something for you later."
Sestak had said during the primary campaign that someone in the Obama administration had offered him a job, but he would not provide details.
On Friday Rep. Darrell Issa, R-Calif., a member of the House Oversight Committee, called for Attorney General Eric H. Holder Jr. to conduct an independent criminal investigation of the Sestak job offer.
"The offering of something of value, monetary or otherwise," could be a crime, he told the Post. "Who sent the president there? What was the conversation between Rahm and President Clinton?"
Clinton is said to be a longtime admirer of Sestak, who had served in a senior defense job in the former president's administration.