Dabour was born in 1837 in Smyrna, Turkey. He studied at the École des Beaux-Arts, Paris, and then in the painting studio of Phillipe-Auguste Jeanron. By 1870, Dabour had immigrated to Baltimore where he established himself as a portrait painter. He painted many prominent figures, including Senator Simon Cameron, Pennsylvania; Governor James Black Groome, Maryland; General Robert E. Lee; and General William Tecumseh Sherman. Dabour later relocated to New York, where he spent the rest of his career.
Dabour exhibited four times with the National Academy of Design, in 1878, 1879, 1882, and 1892 and his work can be found in the permanent collection there. Dabour’s work is also in the permanent collections of the National Portrait Gallery and the Maryland Historical Society.