By David Thomas

David Boies, who became one of America's most prominent lawyers in cases involving Microsoft, the 2000 U.S. presidential election and the fight to legalize same-sex marriage, is stepping down next year as leader of the law firm he co-founded.

The firm's partnership has been in tumult in recent years in part because of Boies' representation of controversial clients like disgraced Hollywood movie producer Harvey Weinstein.

Boies' tenure as chairman of Boies Schiller Flexner ends December 2024, a firm spokesperson said on Friday. A new chairman-will be selected next month, the spokesperson said.

The firm said the 82-year-old Boies is not retiring and will remain a partner. Boies was not immediately available to comment.

Boies Schiller has lost nearly half of its lawyers over the last three years. It now lists 180 lawyers in 13 offices.

The firm has altered its leadership structure in the same period, electing multiple co-managing partners as it looked ahead to a future without its founder.

One of them, Nicholas Gravante, departed for rival law firm Cadwalader, Wickersham & Taft in 2020. Another who briefly held the role, Natasha Harrison, left Boies Schiller last year to found her own firm.

Boies Schiller is now managed by a trio of managing partners, who praised Boies' leadership in a statement on Friday.

"We greatly appreciate the faith David and the rest of the firm has placed in us," partners Matthew Schwartz, Sigrid McCawley and Alan Vickery said in a statement.

In 1997, the same year he started his firm, Boies was hired by the U.S. government for its landmark antitrust case against Microsoft, boosting the firm's reputation as a litigation powerhouse.

He unsuccessfully represented Democrat Al Gore in his U.S. Supreme Court fight with George W. Bush over the 2000 election and later helped overturn California's ban on gay marriage.

In recent years, he was criticized for representing Weinstein, as well as biotechnology company Theranos, which falsely claimed to pioneer blood tests needing minute amounts of blood, and where Boies sat on the board.

(Reporting by David Thomas; Editing by David Bario and Marguerita Choy)