Short answers, pulled from the story.
The Cook Islands became a self-governing territory on the 1st of January 1965. This event marked the creation of a new political role for the islands known initially as Premier.
Albert Henry took office on the 4th of August 1965 as the first person to hold this role. He led the Cook Islands Party during his initial term which lasted until the 25th of July 1978.
A change occurred in 1981 when officials renamed the office to Prime Minister. This shift aligned the local government structure with international naming conventions used by other nations.
Geoffrey Henry began his second major term on the 1st of February 1989. This period lasted until the 29th of July 1999 spanning over ten years while he led the Cook Islands Party.
Mark Brown currently serves as the incumbent starting the 1st of October 2020. These transitions reflect ongoing shifts between the Cook Islands Party and other political groups since the turn of the millennium.