Joe Flanigan (born January 5, 1967) is an American writer and actor best known for his portrayal of the character Major/Lt. Colonel John Sheppard in Stargate Atlantis.
Flanigan was born Joseph Dunnigan III in Los Angeles. He has said that his mother, Nancy, left his father soon after he was born and that his surname was changed to Flanigan after he was adopted by his stepfather, business executive John Flanigan. When he was six years old, his family moved to a small ranch near Reno, Nevada.
From the age of 14, Flanigan attended a boarding school in Ojai, California, where he appeared in the school production of A Streetcar Named Desire. He later earned a history degree at the University of Colorado where he appeared in the play Coriolanus. On the advice of a friend, he took acting classes to overcome his shyness but did not plan to pursue a career in acting. As part of the Junior Year Abroad program, Flanigan spent a year studying at the Sorbonne in Paris, where he learned French.