In a submission to the court, Ms Reno said that the investigation of sex and perjury claims against President Clinton had had "a substantial impact" on how he did his job.
The investigation of "private conduct - the Monica Lewinsky and [Paula] Jones litigation matters," Ms Reno said, "has had a substantial impact on the President's performance of official duties..."
She cited his delivery of the State of the Union address when the scandal was at its height in January, the allocation of Mr Clinton's time and the conduct of foreign affairs.
While Ms Reno's statements were intended to defend Mr Clinton and support arguments by his lawyers that top White House advisers should not have to testify in the Monica Lewinsky investigation, they cut two ways.
Until now, both White House officials and Mr Clinton have been at pains to stress that nothing was diverting them from "business as usual". Mr Clinton has consistently brushed off accusations that he had an affair with Ms Lewinsky when she was a White House trainee and then induced her to lie about it - and left public argument to his considerable team of lawyers.
Now, though, Ms Reno appears to confirm reports that Mr Clinton is spending more time than he has admitted conferring about the case, that it affected his preparations for and delivery of the State of the Union address (which was widely praised, but also bore hallmarks of stress) and may have detracted from the Administration's influence in at least two areas of foreign policy.
His absence from a disastrous public forum defending policy against Iraq in March was widely attributed to the Lewinsky case.
Meanwhile, US passivity towards the stalemate in the Middle East is also blamed by some on the fact that White House attention is concentrated elsewhere.
Until now, the only attempt to catalogue the distracting effects of the Lewinsky case on Mr Clinton was an article by the renowned Watergate journalist Bob Woodward in the Washington Post that was laughed off by the White House.
He had quoted unnamed sources and Clinton friends as saying that the President was angry and upset by the seemingly endless stream of sex allegations, but determined not to show his irritation in public.
Ms Reno's remarks, which appear in court documents released yesterday, mark the second time this week that one of the two main figures in this drama has been done a disservice by someone ostensibly trying to help them.
The former lawyer for Ms Lewinsky, William Ginsburg, said in a furious open letter to the independent prosecutor, Kenneth Starr, that he might "have succeeded in unmasking a sexual relationship between two consenting adults". He later said that his remarks were intended ironically. Both Mr Clinton and Ms Lewinsky have denied that there was any affair.Reuse content