Background
O’Brien was born in Detroit, Michigan where he attended the University of Detroit Jesuit High School.
United States representative politician
O’Brien was born in Detroit, Michigan where he attended the University of Detroit Jesuit High School.
He graduated from the University of Detroit in 1921 and also graduated from the University of Detroit Law School in 1924.
During the First World War, O’Brien served as a private and was assigned to the Students’ Training Corps. He was admitted to the bar in 1924 and commenced practice in Detroit. In 1936, O’Brien defeated incumbent Republican United States. Representative Clarence J. McLeod to be elected as a Democrat from Michigan"s 13th congressional district to the 75th Congress, serving from January 3, 1937 to January 3, 1939.
He lost to McLeod in 1938, but defeated McLeod again in 1940 to be elected to the 77th Congress, and subsequently re-elected to the 78th and 79th Congresses, serving from January 3, 1941 to January 3, 1947.
In 1946, he lost to Republican Howard Aldridge Coffin, but defeated Coffin in 1948 to be elected to the 81st Congress and subsequently re-elected to the 82nd and 83rd Congresses, serving from January 3, 1949 to January 3, 1955. O’Brien was chairman of the Committee on the Post Office and Post Roads during the 75th Congress and a delegate to the 1944 Democratic National Convention in 1944.
He also was an unsuccessful candidate for circuit judge of Michigan"s 3rd Circuit in 1947. After leaving Congress, O"Brien served as assistant corporation counsel of the District of Columbia, assigned to the Civil Proceedings Division from July 11, 1955, until his death in Washington, District of Columbia He is interred in Mount Olivet Cemetery, Detroit, Michigan.