James Joseph Dolan was an Union Army veteran, Grand Army of the Republic member, Republican Party leader, racketeer, Old West businessman and gunman, cattleman, and a key factor in the Lincoln County War, in New Mexico, which launched Billy the Kid to fame.
Dolan was born in Loughrea, County Galway, Ireland and moved to the United States at the age of five with his family. He served in the Union Army from 1863 until the Civil Wars end, after which he moved to Lincoln County, New Mexico. He worked as a clerk for Lawrence Murphy, and by 1874 the two men were business partners in a mercantile and banking operation. The venture was highly successful and profitable, particularly since there was no competition.
Source: Wikipedia