Gravius is first mentioned in historical records as a preacher in Aardenburg. After two years in Batavia undergoing training and waiting to be assigned a missionary post, Gravius went to Formosa in 1647 and was stationed in the village of Soulang. He was credited with introducing the concept of raising draft livestock for ploughing to the aborigines. Gravius translated Christian works into the Siraya language, including a, portions of the Bible and various other tracts, which he accompanied with examples to render the meaning clear to the native Formosans. His linguistic work has been used by later scholars to shed light onto the cultural practices of the Siraya; for example, he noted that the Siraya had no words for gambling, servants or slavery. In the village where Gravius was stationed, he was not only responsible for the religious life of the village, but he was also the senior judicial officerin residence. This dual role was a source of many complaints from the clergy, but the Council of Formosa had ignored these complaints. In 1651 Gravius wrote to Governor Nicolas Verburg complaining about his judicial superior, super-factor Dirck Snoucq, and alleging him to be "a person of shameful and odious character." Unfortunately for Gravius, Verburg took the side of Snoucq, declaring that "this cable of infamous slander had been formed of many strands of abuses and misdeeds of so scandalous and unchristian a nature that they cannot even here be mentioned in detail." Governor Verburg then circumvented the normal procedure for trying a libel case by declining to have it heard by the Council of Formosa, based on the supposition that Frederick Coyett, a member of that council, would rule in favor of Gravius. He fined Gravius 1,000 guilders and then "launched a vitriolic campaign against and against clerical power generally." The authorities in the colony descended into squabbling factions and a commissioner was sent from Batavia to sort out the mess. This commissioner, Willem Verstegen, found fault on both sides and recommended that clergymen be removed from judicial duties to avoid further conflict. Gravius went to Batavia in 1651 to appeal toGovernor-General of the Dutch East IndiesCarel Reyniersz and his follower Joan Maetsuycker against the verdict handed down by Verburg. Gravius remained in Batavia for three years, arguing his case, until he was found blameless and the money taken from him in fines was returned. He returned to the Netherlands as a preacher, where he married again in Veere and eventually died in 1681 in Middelburg.
