He has logged over 4,200 hours flying time in 56 different types of aircraft and over 557 hours in space.

Selected by NASA in January 1990, Searfoss became an astronaut in July 1991. Initially assigned to the Astronaut Office Mission Support Branch, Searfoss was part of a team responsible for crew ingress/strap-in prior to launch and crew egress after landing. He was subsequently assigned to flight software verification in the Shuttle Avionics Integration Laboratory (SAIL). Additionally, he has served as the Astronaut Office representative for both flight crew procedures and Shuttle computer software development.

Searfoss served as STS-58 pilot on the seven-person life science research mission aboard the Space Shuttle Columbia, launching from the Kennedy Space Center on October 18, 1993, and landing at Edwards Air Force Base on November 1, 1993. The crew performed neurovestibular, cardiovascular, cardiopulmonary, metabolic, and musculoskeletal medical experiments on themselves and 48 rats, expanding our knowledge of human and animal physiology both on earth and in spaceflight. In addition, the crew performed 16 engineering tests aboard the Orbiter Columbia and 20 Extended Duration Orbiter Medical Project experiments. The mission was accomplished in 225 orbits of the Earth.

Launching March 22, 1996, Searfoss flew his second mission as pilot of STS-76 aboard the Space Shuttle Atlantis. During this nine-day mission the STS-76 crew performed the third docking of an American spacecraft with the Russian space station Mir. In support of a joint U.S./Russian program, the crew transported to Mir nearly two tons of water, food, supplies, and scientific equipment, as well as U.S. Astronaut Shannon Lucid to begin her six-month stay in space. STS-76 included the first ever spacewalk on a combined Space Shuttle-Space Station complex. The flight crew also conducted scientific investigations, including European Space Agency sponsored biology experiments, the Kidsat earth observations project, and several engineering flight tests. Completed in 145 orbits, STS-76 landed at Edwards Air Force Base, California, on March 31, 1996.