Korean War

For two years beginning in 1952, he was a lieutenant in the Army, serving in the 37th Field Artillery Regiment deployed in the Korean War.

Texas legislature

After practicing law for several years in the Rio Grande Valley, he was elected to the Texas House of Representatives, where he served from 1953 to 1965.

While in the state House, de la Garza was known for sponsoring a large amount of legislation in the fields of education and the environment. He authored bills to protect wetlands, create state-sponsored preschools, and create more international bridges to Mexico. He was the only Hispanic member of the Texas House for the first two years of his tenure, but was joined in 1957 by a second Mexican American member, Oscar M. Laurel of Laredo.

Congress

In 1964, de la Garza, a strong supporter of U.S. President Lyndon B. Johnson, ran for the United States House of Representatives and won a seat in South Texas. From 1981 to 1994, he was the chairman of the Agriculture Committee, leading the way in passing bills that reorganized the agricultural lending system, the farm insurance system, the United States Department of Agriculture, and pesticide laws.

De la Garza voted in favor of the Voting Rights Act of 1965,^[2] the Civil Rights Act of 1968,^[3] and called for smoother relations between the U.S. and Mexico. He worked to improve trade between the two nations and was critical in passing the legislation that enacted the North American Free Trade Agreement (NAFTA).