Steiger was born on 19 February 1936 in Fort Dodge, Iowa, to a mother and father who were farmers. His given name was Eugene Olson. He claims to have lived "in a haunted house with thumps, bumps, doors opening and closing, and men and women walking around all night in period costume."

Steiger claims to have written his first book when he was seven years old, and has published 162 books with over 17 million copies in print, including the biography of Rudolf Valentino, later made into a feature film by British director Ken Russell. From 1970-1973 Steiger wrote a weekly newspaper column, The Strange World Of Brad Steiger. He has authored over 2000 newspaper columns.

Steiger is married to Sherry Hansen Steiger, a former model. He is a former high school teacher, and college instructor. He began writing when he was a school teacher in his native Iowa when he had writings published in Fate Magazine and other publications. Steiger claims to be politically independent, and cynical of politics. He lists his political heroes, however, as Jonathan Swift, Benjamin Franklin, and Thomas Jefferson. When asked about individuals he admired, Steiger listed Ralph Waldo Emerson, Johann Wolfgang von Goethe, Mark Twain, William Shakespeare, Jesus Christ, Mary Magdalene, William James, Frederic William Henry Myers, Rudolf Steiner, Sir William Crookes, and Mario Lanza as those he would have liked to have met.