Joseph was born on the 28th of August, 1876, in Cohoes, New York, and he enlisted in the US Marine Corps in June of 1897 at the age of 21 under the last name of Melvin. He was deployed in support of the Philippine-American War with the Eighth Army Corps and it was his actions as a Private that would earn him the Medal of Honor. The citation reads:

For distinguished conduct in the presence of the enemy in battles, while with the Eighth Army Corps on 25, 27, and March 29, and on April 4, 1899.

Joseph received the Medal of Honor on the 19th of July, 1901 and he left the Marine Corps the following year. He married Grace Cunningham in 1911 and they had two children, Mary and Joseph. Sadly, Grace died at the age of 29 in 1915 when both children were infants and both went to live with her parents. When World War 1 began, Joseph once again enlisted and served for a little over a year, reaching the rank of Sergeant. Joseph H Leonard died on the 23rd of September, 1946 at the age of 70 and he is buried in the Veterans Memorial Grove Cemetery, in Yountville, California.