King, 44, replaces the 69-year-old Thorn, who decided to step down after 10 seasons with the Nets that included two trips to the National Basketball Association Finals.
“He has all of the qualities we’ve been looking for in a candidate: professionalism; good relations with the league, players and agents; and strong communications skills,” Prokhorov said in a statement. “Most importantly, Billy is ambitious. He wants to win.”
King joined the 76ers in 1997 and was promoted to team president after the 2002-03 season. He was fired by the 76ers in December 2007 and replaced by former Nets GM Ed Stefanski.