Senior was born at Hanging Heaton near Dewsbury. He trained at the Leeds School of Art and the Slade School in London.He first exhibited his work in Leeds in 1886 and showed regularly at the Royal Academy from 1892.Senior painted many views of the Yorkshire Coast. His style was influenced, in part, by the French Impressionists.He lived for a time in Ossett, near Wakefield, but he is mostly associated with the area around Runswick Bay on the North Yorkshire coast and the Staithes School of painters.