He was born the son of John and Anne Kennedy in Hammersmith, London.
In the early 1840s, after training as an architect, he moved to live in Bangor, North Wales.
About 1858 he entered into partnership with a Bristol-born architect, John Mechelen Rogers (c.1831–1889), who afterwards moved to London.
During his career he had been involved in some 80 applications to the Incorporated Church Building Society for grants to carry out work in the Bangor diocese.
They had two children, Emily and Henry Du Pre Kennedy.