 In 1889 Irwin was elected into the National Academy of Design as an Associate Academician.In 1873, while in California, Irwin married Adelaide (Adela) Vellejo Curtis (May 29, 1853–1932).She was the daughter of Lucian Curtis, a copper plate engraver and farmer, born in Coventry, Connecticut and Celia Carlton Perkins, born in Philadelphia, Pennsylvania.