Ettinger was born in Atlantic City, New Jersey, the son of Russian Jewish immigrants. Raised Jewish, he later became an atheist. He served as a second lieutenant infantryman in the United States Army during World War II. Severely wounded in battle in Germany, he received the Purple Heart and recovered after several years spent in a Michigan hospital. He earned two master's degrees from Wayne State University (one in physics, one in mathematics) and spent his working career teaching physics and mathematics at both Wayne State University and Highland Park Community college in Michigan.