Sean O’Keefe was administrator of NASA a little more than three years. In that eventful and turbulent period, he dealt with numerous issues. Appointed to cope with a huge cost overrun on the International Space Station, he was soon engulfed in the Columbia shuttle accident and its investigation. Subsequently, he engineered a presidential decision that NASA return to the moon and go eventually to Mars. He also sought to terminate the immensely popular Hubble Space Telescope. The Moon-Mars decision was O’Keefe’s most important achievement, as that involving Hubble was his most controversial action. This essay tracks O’Keefe’s role at NASA as a case study in leadership and change.