Hofheinz was a vital member in almost every aspect of Houston's new baseball franchise, ranging from designing the stadium to securing the funds for the new franchise. Under his leadership and unique vision, the city of Houston constructed two large baseball stadiums: the temporary Colt Stadium and the Astrodome. Hofheinz's enthusiasm spread throughout Houston as the Colt .45s played their inaugural season in 1962 and fans flocked to the new Colt Stadium. While proud to have had a successful season in Houston, Hofheinz's dream was finally realized with the introduction of the Astros and the Astrodome in December of 1964. Hofheinz unveiled what some were calling the "Eighth Wonder of the World" in 1965, and his true passion for this magnificent structure radiated through media outlets as fans packed the new stadium during its first season in 1965. The Judge's vision had come to life as the Astrodome featured bright colors, a larger-than-life scoreboard, and the invention of luxurious sky boxes. Hofheinz routinely hosted movie stars, government officials and a variety of celebrities as everyone was eager to see the futuristic stadium.
Hofheinz continued to develop the area around the stadium adding a theme park and various hotels. He also continued to be the Astrodome's biggest promoter, consistently updating media outlets about stadium upgrades, events and anniversaries. He was one of the key members in the introduction of an artificial playing surface in the Astrodome now referred to as "AstroTurf". While the Astros had little on-field success during Hofheinz's time as owner of the Astros, his vision created an excitement for baseball in Houston that laid the foundation for the great success of the franchise.