After graduating from high school, he enlisted in the United States Army, serving for two years as a paratrooper.

In 1984, Bustamante challenged nine-term incumbent Abraham Kazen in the Democratic primary for Texas's 23rd congressional district.

He was reelected three times from this vast district, which spanned 800 miles from his home in San Antonio to El Paso.

[1] In 1985, Bustamante was elected president of his Democratic freshman class in the U.S. House of Representatives and was assigned to the Committees on Armed Services and Government Operations.

Bustamante called for deficit reduction, but also believed that more money should be spent on education and health care.

His reelection chances were further hampered by redistricting after the 1990 United States Census, which carved the 28th district out of most of Bustamante's territory and left a heavily Republican section of western San Antonio in the 23rd.

[5][6] Bustamante's son, John, a San Antonio-based patent attorney, was an unsuccessful candidate for Texas's 23rd congressional district in the 2012 elections.