William Mulholland was born on September 11, 1855, in the city of Belfast, Northern Ireland which was under British Rule. When William was five, the family returned to their native town of Dublin, also under British rule. Two years later, Willie’s mother died and his father remarried. One day, William ran away from home after getting a thrashing from his father for bad grades. William went to sea and eventually joined the British Merchant Marine at fifteen years old. Over the next four years, Mulholland made nineteen Atlantic crossings to ports all over North America, eventually moving up into the position of navigating officer. He left the ship at the New York harbor and headed west to Michigan, working for the summer and winter on a Great Lakes freighter and Manistee lumber camp. Soon after, he escaped to Cincinnati, spending the next year traveling around the country-side and doing minor repair jobs.
Once Mulholland quit traditional school at the age of 15, he became part of the British Merchant Marine, he was assigned to the Gleniffer. This ship went from Europe to the east coast of America as well as the islands to the south of it. When he got to land, he was reading a lot of books, even though his education was cut short. In one of the books he was reading, he got inspired to explore America with his brother. They went on a boat to Panama, but couldn’t pay the fine, so rode on horseback to California. Once they had finally reached California, they bought two horses and rode down to L.A. They arrived in L.A. in early 1877.