He played in high school with another future NBA star, Gus Johnson, at Akron Central. Their powerful team would go undefeated before losing to Middletown and star Jerry Lucas in the Ohio state high school playoffs. Passing on a scholarship offer to Ohio State University to avoid becoming Lucas's backup there, the 6'10" Thurmond chose Bowling Green State University. He starred well enough there to be drafted by the San Francisco Warriors in 1963.
With the Warriors, Thurmond was an aggressive rebounder-defender who played at the forward position opposite superstar Wilt Chamberlain or was his backup at center. When Wilt was traded back to Philadelphia's new franchise, the 76ers, Thurmond became the All-Star starting center even Wilt said he could be. Among his many accomplishments, Thurmond averaged 21.3 and 22.0 rebounds per game in the 1966-67 and 1967-68 seasons — season averages exceeded by only Bill Russell and Wilt Chamberlain in NBA history. Thurmond also averaged over 20 points per game each season from 1967-68 through 1971-72, and played in seven NBA All-Star Games while with the Warriors. However, while star players like Rick Barry and Jerry Lucas came and went, the Warriors were unable to win a championship with the talented Thurmond at center.
He was traded to the Chicago Bulls for Clifford Ray prior to the 1974-75 season (ironically, Golden State did win a championship that season with Ray at center). On October 18, 1974 against the Atlanta Hawks, in his debut as a Chicago Bull, he recorded 22 points, 14 rebounds, 13 assists and 12 blocked shots, thus becoming the first player in NBA history to record a quadruple-double. He was then traded to Cleveland Cavaliers 13 games into the following season. In Cleveland, the now 35-year-old Thurmond came off the bench for the injured Jim Chones to lead Cleveland to the East Conference Finals before the Cavaliers lost to the star-studded Boston Celtics in 1976.
After retirement, Nate returned to San Francisco and opened a well-known restaurant after a brief attempt at broadcasting. In 1996 he was named one of the 50 Greatest Players in NBA History, and he remains one of the greatest rebounders and shot blockers in basketball history.