 He was a member of the board of education of Kennett from 1928 to 1936 and a member of the board of regents of Southeast Missouri State College from 1933 to 1948.Zimmerman was elected a Democrat to the U.S. House of Representatives in 1934 and was re-elected six additional times until his death on April 7, 1948 in Washington, D.C.He is interred at Oak Ridge Cemetery in Kennett, Missouri.