M'Nok was a Starfleet crewman who served aboard the USS Defiant. M'Nok was assigned to the Gamma Quadrant exploration mission the Defiant engaged in 2376.
After Mikaela Leishman was injured when the Defiant entered a Cheka subspace web, Ezri Dax had M'Nok and Tariq Rahim take Leishman to the medical bay. (DS9 - Mission Gamma novel: This Gray Spirit)
When Dax was briefly separated from Ezri, M'Nok was assigned to the biochem lab to look after the Trill symbiont. (DS9 - Mission Gamma novel: Cathedral)