Dorgan was born in
San Francisco on April 29, 1877. He was one of at least eleven children – six sons and five daughters – of Thomas J. and Anna Dorgan. His brother
John L. "Ike" Dorgan (born April 1879) was publicity manager for the
Madison Square Garden, and his brother
Richard W. "Dick" Dorgan (born September 1892) was an illustrator and cartoonist.
Polytechnic High School teachers Rosey Murdoch and Maria Van Vieck recognized and encouraged Tad's talent as an artist. When Dorgan was a child, he lost several fingers of his right hand in an accident whose details are unclear.
Cosmopolitan writer
O. O. McIntyre, a friend of Dorgan's, wrote that when Dorgan "was eight, he was fooling around on a house-moving job and attempted to ride a shovel on a rope that was propelled by a big pulley. He turned his head for a second and his right hand was caught in a pulley, crushing off four fingers of that right hand, which was reduced to a thumb and a piece of knuckle."
Henry Morton Robinson's description of the incident is largely the same, except that he said it took place when Dorgan was nine.
Westbrook Pegler, another friend of Dorgan's, wrote that Dorgan had lost "the first two fingers and half of the palm of his right hand" in an incident with a
buzzsaw. Comics historian John Adcock noted that, of all the "dozens of different stories", only McIntyre's version accorded with the statement on Dorgan's draft card that he had "all fingers except thumb off of right hand". After the amputation, Dorgan took up drawing for therapy. When he was 14 he joined the art staff of the
San Francisco Bulletin. ==Strips and panels==