Jabba hired him as part of his Weequay employment program. Since Mar-Nuk had some experience as a mechanic, Jabba put him to work on his small fleet of skiffs. Though he had no previous experience with that type of vehicle, Mar-Nuk quickly became the best skiff mechanic under Jabba's employ. When Mar-Nuk's time in the employment program expired, Jabba offered him a permanent position as skiffmaster.
Mar-Nuk took his job very seriously and insisted that he train every skiff crew member himself. Mar-Nuk was unhappy when Jabba announced that he'd be using the skiffs to execute some prisoners, but was unwilling to challenge his employer. He insisted that he go along too, just in case anything went wrong, which it did. Sadly, his padded tunic was no match for a lightsaber.