He married Mary Ellen (Nellie) Meriwether Henderson (1886–1976), also a teacher and civil rights advocate, as well as active with the Girl Scouts and League of Women Voters. They moved to Falls Church, Virginia in 1910 shortly after their marriage, and both helped at the Henderson family store. They lived at 307 South Maple Street (originally 307 W. Fairfax Street) for decades; Edwin Henderson also took the colored streetcar line across the Potomac River to his job with the D.C. Public Schools. They also had a summer home at Highland Beach on Chesapeake Bay near Annapolis, Maryland. The Hendersons remained married for 63 years until her death (almost a year before his demise), and were survived by both their sons: Dr. James H. M. Henderson (who became director of Tuskegee's Carver Research Foundation), Dr. Edwin M. Henderson (who became a dentist in the District of Columbia). Career Upon graduating as a teacher in 1904, Henderson taught (and later directed) physical education in the D.C. public schools for five decades. During his first three summer breaks, he attended summer sessions at Harvard University to study medicine or health and physical education. There, Henderson also learned the then-new game of basketball, which he introduced to other young black men at the 12th Street (Colored) YMCA upon returning to Washington, D.C. Soon, they were playing teams from Baltimore, Philadelphia and New York. His D.C. teams (Howard University adopted the 12th street team as its first varsity basketball team) won the national basketball championships in 1909 and 1910. From those early years through the 1950s, Henderson also played and coached basketball, as well as refereed football and baseball contests and occasionally sparred in the boxing ring. He helped organize the first all-black amateur athletic association, the Interscholastic Athletic Association (1906), the Washington, D.C. Public School Athletic League (1906) and the Eastern Board of Officials (1905) (a training center that, for decades was the go-to pool for highly qualified African American referees). Henderson taught and influenced perhaps hundreds of thousands of Washington area schoolchildren in basketball, including Duke Ellington and Charles Drew. From 1926 until 1954, Henderson directed physical education for African American children in the segregated Washington, D.C. school system. He used sports to combat truancy, as well as instill character, forming teams in each fifth and sixth grade classroom. In 1943 his contributions were recognized by his being named to the National Council