Donahey left school early to become a printer; in addition to working as a newspaper editor, he owned his own printing company. After serving in local and county government as a school board member and county auditor in the early 1900s, in 1912 he won election as Ohio's state auditor, and he served until 1921. After an unsuccessful campaign for governor in 1920, in 1922 Donahey won the governorship. He was reelected in 1924 and 1926, and served from 1923 to 1929. In 1934, Donahey won election to the U.S. Senate, and he served one term, 1935 to 1941.