He began working as a young donkey boy to Lucie, Lady Duff-Gordon and learned English from her.
He opened an antiquities shop in Luxor in the early 1880s and became well-known among especially British and French archaeologists and dealers.
[2] Americans Theodore M. Davis and Emma Andrews bought a number of pieces from Mohassib the entire time they were travelling through Egypt (1889-1913).
[3] E. A. Wallis Budge of the British Museum corresponded with Mohassib, who would regularly arrange to purchase items from him.
Upon his death on April 6, 1928, in Luxor, Percy Newberry memorialized him in the Journal of Egyptian Archaeology.