When Gabriel Castor was born on 30 May 1786, in Pittsburgh, Allegheny, Pennsylvania, United States, his father, Benjamin Castor, was 45 and his mother, Ruth Thompson, was 43. He had at least 7 sons and 3 daughters with Catherine Louisa Huffman. He lived in Jefferson, Allegheny, Pennsylvania, United States for about 10 years and Jefferson Township, Allegheny, Pennsylvania, United States in 1860. He registered for military service in 1812. He died on 27 March 1863, in Finleyville, Washington, Pennsylvania, United States, at the age of 76, and was buried in James Chapel Cemetery, Gastonville, Union Township, Washington, Pennsylvania, United States.