Jack was born in 1881, although his birthplace is unknown. His father is in the state penitentiary, and his mother is deceased. The other newsies think his parents are in Santa Fe to find a home.
He is known to have been to the refuge, a jail for kids run by one of the movies antagonists,Warden Snyder.
Jack is also known to want to run from his past and go to Santa Fe.
Jack is a dreamer.
Jack recieved his nickname, Cowboy, for his dream of going west to Santa Fe, as well as his signature cowboy hat, bandana and lasso tied like a belt. His real name is Francis Sullivan.
Jack created the idea of the strike. With a little bit of help from Spot Conlon, his intimidating Brooklyn ally, and the new newsie David, the newsies started the strike. But during a newsie rally at Irving Hall, he is arrested and his real name, Francis Sullivan, is revealed in court to the surprise of the other newsies. In an attempt to break out, he is offered a deal from Pulitzer to sell newspapers again and receive money for his trip to Santa Fe. At first he refuses, but when Pulitzer threatens to put the other newsboys in the Refuge, he accepts it. The enraged newsies start to hate Jack, thinking he betrayed them, but he saves David, Les and their sister Sarah from the Delancey brothers and they reunite. The newsies eventually win the strike. Jack is offered a chance to go to Santa Fe by the governor, but refuses in favor of staying with his newsie family .