Thomas Edward Patrick Brady Jr. was born in San Mateo, California on August 3, 1977, the only son and fourth child of Galynn Patricia (née Johnson) and Thomas Brady Sr.[10] He has three older sisters, Nancy, Julie and Maureen,[11] and was raised as a Catholic. His father is of Irish descent, while his mother has German, Norwegian, and Swedish ancestry.[12] Two of Brady's great-great-grandparents on his father's side, John and Bridget Brady, were Irish refugees from the Great Famine who moved to San Francisco from Boston before the American Civil War. They were accompanied by Bridget's sister Ann and her husband Lawrence Meegan, the parents of the 19th-century American Major League Baseball player "Steady" Pete Meegan.