Rev. Horace S. Graves was born in Paducah, Kentucky and attended Wilberforce College in Ohio where he completed a degree and divinity coursework.

He participated in the AME district convention in Mount Pleasant, Iowa in 1897 though he is not identified with a specific congregation. Graves is referenced as the secretary of the convention in 1899, and later that year is said to have become the pastor of the Galesburg AME Church on September 1.

Rev. Graves led a crusade on Court Ave. in 1904 and was active in discrimination issues. He came to Des Moines in May 1902 and served at St. Paul AME until 1906 when he was transferred to St. Paul, Minnesota in April. Rev. Graves continued to visit Iowa and participated in church events in Cedar Rapids in 1909 and Des Moines in 1911.

He became pastor of the Ebenezer AME Church in Evanston, Illinois in 1911 and ministered there until facing health problems in early 1913. He traveled to North Carolina by April but died there in July. Rev. Graves' remains were returned to Illinois and his funeral services and burial were in Evanston.