John McDuffie (September 25, 1883 – November 1, 1950) was born in River Ridge, Alabama in Monroe County on September 25, 1883. He was educated by private tutors. He attended college at Southern University (now Birmingham–Southern College) in Greensboro and later attended Alabama Polytechnic Institute in Auburn, Alabama, where he in graduated in 1904. McDuffie went to Law School at The University of Alabama and graduated there in 1908. He was admitted to the bar the same year.
A Democrat, he was elected to the Alabama House of Representatives in 1907 and served until 1911. He later became a prosecutor for the First Judicial Circuit Court of Alabama and served there until 1919.
He was elected to the United States House of Representatives in 1918, and served from March 4, 1919, until his resignation on March 2, 1935. During his tenure in the House he served as Minority Whip for 71st Congress, and later as Majority Whip for 72nd Congress. He also served as chairman of the Committee on Insular Affairs in 73rd and 74th Congress. He co-authored the Philippine Independence Act which provided for self-government of the Philippines and for Filipino independence from the United States after a period of ten years.
In 1935, President Franklin Delano Roosevelt appointed McDuffie to a seat on the U.S. District Court for the Southern District of Alabama where he served until his death in Mobile, Alabama on November 1, 1950. He is interred in Pine Crest Cemetery.