Kerwin was born in Oak Park, Illinois, on February 19, 1932, as the seventh child of an Irish Catholic family.

He graduated in 1953 with a Bachelor of Arts degree, magna cum laude, in philosophy with a minor in pre-med, ranked eighth in a class of 380 students.

With him for the initial activation and 28-day flight qualification operations of the Skylab Orbital Workshop were Charles "Pete" Conrad (spacecraft commander) and Paul J. Weitz (Pilot).

In this capacity, he served as liaison between NASA's Office of Space Tracking and Data Systems and Australia's Commonwealth Scientific and Industrial Research Organisation.

There, he was responsible for direction and coordination of medical support to operational crewed spacecraft programs, including health care and maintenance of the astronauts and their families; for direction of life services, supporting research and light experiment project; and for managing JSC earth sciences and scientific efforts in lunar and planetary research.

In 1986, he issued a report on the deaths of the crew killed in the Challenger disaster to Associate Administrator for Space Flight, Richard H.

In 1994–95 he led the Houston liaison group for Lockheed Martin's FGB contract, the procurement of the Russian "space tug" which has become the first element of the ISS.

In addition to his duties at Wyle, Kerwin serves on the Board of Directors of the National Space Biomedical Research Institute (NSBRI) as an industry representative.

[17] The three Skylab astronaut crews were awarded the 1973 Robert J. Collier Trophy "For proving beyond question the value of man in future explorations of space and the production of data of benefit to all the people on Earth.

"[18][19] Gerald Carr accepted the 1975 Dr. Robert H. Goddard Memorial Trophy from President Ford, awarded to the Skylab astronauts.

[22] Kerwin is co-author, along with fellow astronaut Owen K. Garriott and writer David Hitt, of Homesteading Space, a history of the Skylab program published in 2008.