Born in 1870 in New Haven, Connecticut, Robert H. Bonner was the son of Willis and Elizabeth Bonner. His father, a carpenter, was active in Republican politics in New Haven. A brother, Frederick Douglass Bonner, graduated from Yale College in 1901.
Along with fellow Black students Charles H. Boyer, Orishatukeh Faduma, and Henry H. Proctor, Robert H. Bonner was a member of an incarnation of the Colored Yale Quartet as a student.
Bonner was part of a core group of radical Black Bostonites who supported William Monroe Trotter in the founding of the Niagara Movement. Sometime after graduating from Yale, he moved to Cambridge, Massachusetts. Although some sources identify him as a lawyer, he is listed in the 1918 city directory as a steward of the Union Club of Boston. Bonner died in 1926, survived by his wife Marie and children. He is buried in Grove Street Cemetery.
Image citation: Detail from photograph of Robert H. Bonner, Orishatukeh Faduma, Charles H. Boyer, and Henry H. Proctor, Schomburg Center for Research in Black Culture, Jean Blackwell Hutson Research and Reference Division, The New York Public Library. Accessed via New York Public Library Digital Collections.