Ken Starr, who led the investigation that led to the impeachment of former US president Bill Clinton for lying about his affair with White House intern Monica Lewinsky, died on Tuesday, his family announced.
Starr, 76, died in Houston, Texas, of complications from surgery, his family said.
A former judge and conservative legal stalwart, Starr was best known for leading the inquiry that resulted in Mr Clinton's December 1998 impeachment by the Republican-controlled House of Representatives.
He was acquitted by the Senate the following year.
Starr's involvement with Mr Clinton began when he was appointed special counsel in 1994 to investigate a land deal known as Whitewater, involving Bill and Hillary Clinton.
That expanded into an investigation of the president's affair with Ms Lewinsky, then 24, which Mr Clinton initially denied.
The Starr Report documented the president's relationship with Ms Lewinski in graphic detail and resulted in Mr Clinton being accused of perjury.
Starr later wrote a book about the probe — Contempt: A Memoir of the Clinton Investigation — and Time magazine chose Mr Clinton and Starr as their "Men of the Year" in 1998.
Named a judge at the age of 37 by president Ronald Reagan, Starr went on to serve as solicitor general from 1989 to 1993 under former president George HW Bush, arguing 25 cases before the Supreme Court.
He was president of Baylor University from 2010 to 2016, when he left over the handling of sexual assault cases by American football players at the Baptist school.
In January 2020, Starr joined the legal team defending former president Donald Trump in his first impeachment trial before the Senate.
Like Mr Clinton, Mr Trump was impeached by the House but acquitted by the Senate.
Republican Senator minority leader Mitch McConnell praised Starr as a "a brilliant litigator, an impressive leader and a devoted patriot".
"Ken poured his remarkable energy and talent into promoting justice, defending the Constitution and upholding the rule of law, Mr McConnell said.
Ms Lewinsky, in a February 2018 article in Vanity Fair, lashed out at the investigation that put her in the centre of a political firestorm.
She said she had a chance meeting with Starr in December 2017 at a New York restaurant.
"I felt determined, then and there, to remind him that, 20 years before, he and his team of prosecutors hadn't hounded and terrorised just me but also my family," she said.
Looking for an apology, Ms Lewinsky said she told Starr that while she wished she had made "different choices", she would have liked his office to have done the same.
Ms Lewinsky said Starr gave an "inscrutable smile" and replied, "I know. It was unfortunate."