Matthew Leonard was born in Philadelphia, Pennsylvania on 20 July 1886. He was the son of Irish Roman Catholic parents, John Leonard and Sarah Barry (b. 1853). His father's exact Irish origins are not clear but his mother is believed to have hailed from Toome, a village in northwest Co Antrim. When the couple emigrated to the USA is not clear but they returned to Ireland sometime prior to 1890 where Matthew's only sibling was born, Mary. His father seemingly passed away around 1895.
Following the death of Matthew's father, he, his mother and sister went to live with his maternal grandmother Bridget Barry, a farmer, in Toome, Co Antrim. They appear at 8 Brecart in that village on the 1901 census. After leaving school Matthew worked for a grocers. He and his family relocated to Belfast by the time of the 1911 census and show up living at 23 Chatsworth Street, Pottinger, east Belfast, Co Down. Matthew is described as a grocer's assistant and his sister Mary as a machinist. He later went to work a jewellers, Joseph Rea's, in Ann Street, Belfast City Centre which is still in operation today. He later left to go to sea before Easter 1912.
Matthew was on the Titanic for her delivery trip from Belfast to Southampton. When he signed on again, in Southampton, on 4 April 1912, he gave his address as 45 Chatsworth Street, Belfast. As a third class steward he could expect monthly wages of £3, 15s. The Titanic was his first ship.
Matthew Leonard died in the sinking. His body, if recovered, was never identified.