In the late 1960s, he worked in Washington, D.C., as legislative aide to U.S. Senator Ralph Yarborough. After managing the presidential campaign of former Senator Fred R. Harris of Oklahoma in 1976, he returned to Texas to become the Editor of the magazine The Texas Observer. His first attempt at public office was an unsuccessful bid for the Democratic nomination for the Texas Railroad Commission, which regulates the oil and natural gas industries, rather than the railroads the name of the commission would seem to indicate. In 1982, Hightower was elected Agricultural Commissioner, having unseated fellow Democrat Reagan V. Brown, who had ordered a quarantine of fruit coming into Texas from California. He served as agriculture commissioner until he was unseated in 1990 by the Democrat-turned-Republican Rick Perry, later the governor of Texas. His tenure was noted for fostering organic production, alternative crops, direct marketing by small farmers, and strong gross materials regulations. During that time, he also became a leading national spokesman for Democrats and endorsed Jesse Jackson for President in 1988. Three of Hightower’s aides at the Agriculture Commission, Mike Moeller, Pete McRae, and Billie Quicksall were indicted and convicted on bribery charges related to Hightower's fund raising activities. The activities involved shaking down seed dealers under the departments oversight to make contributions to Hightower’s reelection campaign. While Hightower was not involved in the plot, it contributed to his defeat by Perry.