Acosta's family, like many other Portuguese Jews escaping from the persecutions of the Inquisition, fled from Portugal to Holland.
Jan Acosta spent several years travelling across Europe. He owned a brokerage office in Hamburg but it failed, and he was ruined.
Invited by the Russian vice consul in Hamburg, he came to Petersburg.
In 1714 Peter I appointed Jan Acosta court jester. As the Russian historian Shubinsky has remarked, "Thanks to a funny figure, knowledge of almost all European languages and an ability, to make fun of and to please everyone (which is characteristic of the Jewish tribe), he managed to become a court jester". Shubinski writes that Acosta knew the Holy Scripture very well and Peter liked to dispute with him on theological topics. In his memoirs, Berkholtz, a German resident in Russia in those days, mentioned a dispute of this kind which took place right on the porch of the Summer Palace.
Unfortunately we do not know whether Acosta kept to his Judaism openly. At any rate his origin was not a secret and among the courtiers he was known as "the Portuguese Jew Lacosta".
In 1719 there was a conflict between Acosta and the court physician Lestok. The latter desired Acosta's daughter. The angered father ordered his servants to lie in wait for Lestok at night and catch him at the scene of the crime. Taken unawares, Lestok unsheathed his sword and waving it about escaped his attackers. This fact became known and Peter I learned about it too. He ordered Lestok into exile from Petersburg in spite of the latter's protestations that he "was in love with the girl and wanted to marry her".
In gratitude for Acosta's zealous service Peter the Great conferred on him the humorous title the King of the Samoeds and gave him the uninhabited sandy island Sommer in the Finnish Gulf.
Acosta outlived Peter. He remained a court jester during the reign of Anna Ioannovna, but his subsequent fate is unknown.