William J. Clothier was a top American tennis player in the early 1900s and reached the singles final of the United States Championships three times.

Two years later, in 1906, Clothier achieved his greatest success by emphatically beating Beals Wright in the final in three straight sets at the Newport Casino.

He was a member of the winning USA Davis Cup Team in 1905 and 1909 and won both his singles matches in the 1909 final against the British Isles.

[4] Together with his son, William J. Clothier II, they two won the national father-son title held at Longwood Cricket Club twice in 1935 and 1936.

Clothier is interred in the family plot at West Laurel Hill Cemetery, Summit Section, in Bala Cynwyd, Pennsylvania.