Lesley McCreath married Margaret Bailly. He was a Consulting Chemist

They had four children, two of whom died as babies:

Andrew Smith McCreath born c. March 1909. Died 20 October 1909, New York

Margaret McCreath born c. February 1911. Died 14 December 1911., Pittsburgh.

Lesley McCreath, Jnr. born 27 May 1912

James McCreath born 13 November 1914, Harrisburg. Died 13 November 1937, Cincinatti, Ohio.

Lesley Robert McCreath died  on  in Harrisburg, Pennsylvania.