Baldwin was a United States Army Air Corps pilot from 1943 to 1946, flying B-25 Mitchells in the South West Pacific theatre of World War II on low-level bombing raids.

In 1959, he returned to private practice in Marshall with his brother, Scotty Baldwin, and remained there until his appointment to the federal bench in 1968.

[4] Baldwin was nominated by President Lyndon B. Johnson on May 29, 1968, to a seat on the United States Court of Customs and Patent Appeals vacated by Judge Isaac Jack Martin.

He was reassigned by operation of law on October 1, 1982, to the United States Court of Appeals for the Federal Circuit, to a new seat authorized by 96 Stat.

[4] His chamber papers and personal records were donated to South Texas College of Law Houston in 2005.