His postgraduate medical training (internal medicine, hematology and oncology) was at the University of California, Los Angeles (UCLA) from 1970 to 1973.

His postdoctoral studies at UCLA were funded by the U.S. National Institutes of Health (NIH) and the Leukemia Society of America, where he was the Bogart Fellow and Scholar.

During this time he volunteered his expertise in bone marrow transplants to the USSR, for the victims of radiation poisoning incurred during the Chernobyl nuclear disaster.

From 1993 to 1999, Gale was Senior Physician and Corporate Director of Bone Marrow and Blood Cell Transplantation at Salick Health Care (SHC), Inc. in Los Angeles (now Aptium Oncology), a subsidiary of AstraZeneca.

From 2000 to 2004 he was Senior Vice President for Medical Affairs at Antigenics Inc., in New York where he was responsible for design, implementation and analysis of clinical trials of cancer vaccines.

His activities included development and execution of clinical trials in blood and bone marrow cancers, transplantation and immune disorders.

Gale is regarded as a world expert on the medical response to nuclear and radiation accidents and has participated in rescue efforts at Chernobyl, Goiânia, Tokaimura, Fukushima and others.

In 2011 Gale was called to Japan to deal with medical consequences of the Fukushima nuclear power station accident.

In addition to his academic publications, Gale has written popular books on the Chernobyl accident and US nuclear energy policy.

He has written parts of screenplays for, and appeared in, several movies including Chernobyl: The Final Warning (with Jon Voight),[4] Fat Man and Little Boy (with Paul Newman), and City of Joy (with Patrick Swazye).