Walt played 13 years as a guard and tackle in the NFL with the Duluth Eskimos (1926–1927), Pottsville Maroons (1928), Chicago Cardinals (1929–1933), Chicago Bears (1934), Green Bay Packers (1935–1936), and Pittsburgh Pirates (1937–1938).

Kiesling also spent 25 years as a coach or aide for NFL teams, including seven years as head coach of the Pittsburgh Pirates/Steelers from 1939 to 1942 and 1954 to 1956. He provided Pittsburgh's first franchise-winning season in 1942. He was posthumously inducted into the Pro Football Hall of Fame in 1966 and was named to the NFL 1920s All-Decade Team in 1969.