Born in Chambers County, Alabama, Pepper established a legal practice in Perry, Florida after graduating from Harvard Law School. After serving a single term in the Florida House of Representatives, Pepper won a 1936 special election to succeed Senator Duncan U. Fletcher. Pepper became one of the most prominent liberals in Congress, supporting legislation such as the Fair Labor Standards Act of 1938. After World War II, Pepper's conciliatory views towards the Soviet Union and opposition to President Harry Truman's 1948 re-nomination engendered opposition within the party. Pepper lost the 1950 Senate Democratic primary to Congressman George Smathers and returned to private legal practice the following year.