Joseph claimed a five-wicket haul in his debut in Adelaide before taking 7-68 in Brisbane, where West Indies recorded their first test win Down Under since 1997.
Joseph returned to a hero's welcome in Guyana and has now been promoted from the cricket board's current franchise contract to an international retainer contract.
"His extraordinary talent and steadfast dedication serve as the cornerstone of our team's recent triumph at the Gabba, and such promise merits its due recognition," CWI Director Enoch Lewis said in a statement on Thursday.
"Shamar has not just been rewarded with a retained contract, he has earned it."
CWI also handed Barbados fast bowler Chemar Holde (25) a franchise contract.
"We have also offered Chemar Holder a franchise contract as we double down on securing the best fast-bowling talent available," director of cricket Miles Bascombe said.
"We are excited to see both men continue to excel."
