In 1960, Ashe was precluded from competing against Caucasian youths in segregated Richmond during the school year and unable to use the city's indoor courts that were closed to black players. He accepted an offer from Richard Hudlin, a 62-year-old St. Louis teacher, tennis coach and friend of Dr. Johnson, to move to St. Louis and spend his senior year attending Sumner High School, where he could compete more freely. Ashe lived with Hudlin and his family for the year, during which time Hudlin coached and encouraged him to develop the serve-and-volley game that Ashe's now stronger physique allowed. Ashe was able to practice at the National Guard Armory indoor courts and in 1961, after lobbying by Dr. Johnson, was granted permission to compete in the previously segregated U.S. Interscholastic tournament and won it for the school.
In December 1960 and again in 1963, Ashe was featured in Sports Illustrated, appearing in their Faces in the Crowd segment. He became the first African American to win the National Junior Indoor tennis title and was awarded a tennis scholarship to the University of California, Los Angeles (UCLA) in 1963. During his time at UCLA, he was coached by J. D. Morgan and practiced regularly with his sporting idol, Pancho Gonzales, who lived nearby and helped hone his game. Ashe was also a member of the ROTC, which required him to enter active military service after graduation in exchange for money for tuition. He was active in other things, joining the Upsilon chapter of the Kappa Alpha Psi fraternity on campus. After graduating with a bachelor's degree in Business Administration, Ashe joined the United States Army on August 4, 1966. Ashe completed his basic training in Washington and was later commissioned as a second lieutenant in the Adjutant General Corps. He was assigned to the United States Military Academy at West Point where he worked as a data processor. During his time at West Point, Ashe headed the academy's tennis program. He was promoted to 1st lieutenant on February 23, 1968, and was discharged from the Army in 1969.