After holding the position for two years went to study at the University of Papua New Guinea, where he obtained a bachelor of law degree in 1989.

While member of the Nitijeļā Zackios was Chief Negotiator for the Compact of Free Association between the Marshall Islands during the renegotiations which lasted between 2001 and 2004.

[2] He also helped negotiate a deal with the United States that extended its use of the Ronald Reagan Ballistic Missile Defense Test Site until at least 2066.

[2] After having served three terms Zackios lost his seat during the 2011 Marshallese general election after postal ballots from the United States were counted.

[4] In autumn 2019, leaders of the five Micronesian countries, consisting of the Marshall Islands, Nauru, Palau, Kiribati and the Federated States of Micronesia, made Zackios their nominee to succeed Meg Taylor in the position of Secretary General of the Pacific Islands Forum.

[7] In February 2021, after Henry Puna was instead elected to the post with the support of Australia and New Zealand, the five Micronesian countries withdrew from the Forum.