He was employed in the office of the county clerk of Greer County, Oklahoma from 1924 to 1926, and as court clerk of Greer County from 1926 to 1935. He served as chief clerk of the board of affairs of the State of Oklahoma in 1935 and 1936. He engaged as a building contractor in Oklahoma City in 1937 and 1938 and in the life insurance business 1938-1941. Wickersham also worked as a real estate, insurance, and investment broker. In later years when he had gray hair, he would dress up as the "Uncle Sam" character and appear at political rallies.
Wickersham was elected as a Democrat to the 77th Congress to fill the vacancy caused by the death of Sam C. Massingale. He was reelected to the 78th and 79th Congresses and served from April 1, 1941, to January 3, 1947. He was an unsuccessful candidate for renomination in 1946, but was reelected to the 81st and to the three succeeding Congresses (January 3, 1949-January 3, 1957). He was not renominated in 1956 and 1958. He succeeded in his election to the 87th and to the 88th Congresses (January 3, 1961-January 3, 1965). He was an unsuccessful candidate for renomination in 1964 to the 89th Congress.
He served as member of the Oklahoma House of Representatives, January 3, 1971-January 3, 1979, and again from February 9, 1988, until his death in Oklahoma City, Oklahoma, on March 15, 1988.