Swigert was originally part of Apollo support and backup crews, not the prime crew for Apollo 13. Just days before launch, he replaced Ken Mattingly as Command Module Pilot after Mattingly was exposed to German measles. That sudden change placed Swigert in one of the most demanding roles of the Apollo program with very little warning.

During Apollo 13, an oxygen tank explosion forced Swigert, Jim Lovell, and Fred Haise to abandon the Moon landing and focus on survival. Swigert helped preserve and later power up the command module Odyssey for reentry — open definition after the crew spent most of the return in the lunar module Aquarius. After leaving NASA, he entered politics and was elected to the United States House of Representatives from Colorado in 1982, but he died of cancer before taking office.

Swigert's background fit the broader pattern of the early astronaut corps: technical training, operational discipline, and a career built around difficult work before spaceflight. His formal education included University of Colorado (B.S. Mechanical Engineering, 1953), Rensselaer Polytechnic Institute (M.S. Aerospace Science, 1965), and University of Hartford (M.B.A., 1967). His service background is recorded as United States Air Force and Air National Guard, Fighter pilot.

Swigert's flown space career centered on Apollo 13, where he served as Command Module Pilot. Planned lunar landing mission that became a survival and recovery mission after an oxygen tank explosion. The crew used the lunar module as a lifeboat, looped around the Moon, and returned safely to Earth without landing.