Walter Evan Black, Jr. was born in Baltimore on July 26, 1926, the son of Walter Evan Black and Margaret (Rice) Black. On June 30, 1951, he married Catharine S. Foster. He earned his A.B. degree (magna cum laude) from Harvard University in 1947 and received a LL.B. degree from Harvard University Law School in 1949.

Following law school, Judge Black joined the firm of Hinkley and Singley as an associate, where he remained until 1953. From 1953-55, Black served as an Assistant United States Attorney in the District of Maryland. In 1956, he returned to private practice, rejoining the firm of Hinkley and Singley, where he became partner.

Four months later, he was appointed United States Attorney, returning to private practice in 1957 as a partner in Hinkley and Singley. In 1968, Judge Black became a partner of the successor firm of Clapp, Somerville, Black and Honemann. Black was nominated for appointment as a United States District Judge by President Reagan on March 11, 1982, and his nomination was confirmed by the Senate on April 20, 1982. On March 8, 1991 he was elevated to Chief Judge until he stepped down on October 21, 1994 to assume senior status.

During his career, he also served as Chairman of the Baltimore City Board of Municipal and Zoning Appeals from 1963-67; on the Board of Directors of the Baltimore Urban League from 1963-69 and 1976-82; and on the Board of Directors for Union Memorial Hospital and the Hospital for Consumptives of Maryland.