Discharged from the Navy as Lieutenant Commander in 1946, he returned to Austin to re-enter the practice of law in partnership with the late Judge Herman Jones. He was a member of the City Council of Austin from 1946-1948, serving as Mayor pro tempore in 1947-1948. Thornberry was elected in 1948 to the 81st Session of the United States Congress as Representative of the 10th Congressional District of Texas. He was re-elected to each Congress until his resignation in December, 1963. During his time in Congress, he was a member of the Rules Committee of the House of Representatives from January of 1955, until his resignation.
He was appointed by President John F. Kennedy as a United States District Judge for the Western District of Texas in 1963, and commissioned by President Lyndon B. Johnson, and sworn in as a United States Judge in El Paso, Texas, on December 21, 1963. He was appointed and commissioned by President Johnson as a United States Circuit Judge (Fifth Circuit) in 1965, and sworn into office as a Circuit Judge on July 3, 1965, at the LBJ Ranch. He took senior status December 21, 1978. During his service on the Fifth Circuit Court of Appeals, he participated in decisions including many civil rights cases of the 1960s and 1970s. He served as a member of the Judicial Conference Committee to Implement the Criminal Justice Act from 1964 to 1979, and the Fifth Judicial Council Committee on Criminal Justice Act in 1967.
Thornberry received the Boy Scouts of America Silver Beaver Award in 1948. He served as a board member of Gallaudet University, Washington, D.C. (the only senior college for the deaf in the world) from 1949 until his resignation from Congress, at which time he was named honorary life member of the Gallaudet Board. He was a Delegate-at-Large at the National Democratic Convention in 1956 and 1960. He was an Honorary Member of the Order of the Coif, an honorary legal organization and was chosen as a Distinguished Alumnus of the University of Texas in 1965. He was elected to the Austin High School Hall of Honor in May, 1983. He received the Leon Green Award from the Texas Law Review Association of the University of Texas School of Law in April, 1986. Judge Thornberry was a past member of the Texas Bar Association and a current member of the Travis County Bar Association. He was a member of the Texas Society of Sons of the American Revolution and a 33rd Degree KCCH Member of the Austin Scottish Rite Bodies. He was an honorary member of Kiwanis International, and served as Potentate of the Ben Hur Temple Shrine in 1948. He died peacefully at home in Austin on Tuesday, December 12, 1995. Source
30° 15.925, -097° 43.635
Texas State Cemetery