Heine was the first woman to lead any sovereign country in Micronesia and the first person from the Marshall Islands to earn a doctorate.

The legislature selected her for the presidency two weeks into the session in January 2016 after a motion of no confidence removed her predecessor, Casten Nemra.

Over the following years she served as a board member of the East–West Center and pro-chancellor of the University of the South Pacific in addition to her role as a legislator.

[6] Her grandfather was Carl Heine, an Australian-born Congregationalist missionary who married a Marshallese woman and was executed by the Japanese during World War II.

[12] She was also a member of the Teacher Standards and Licensing Board, the Commission on Education in Micronesia, and the Human Resources in Health Task Force.

[13] Heine first became a member of the Nitijeļā representing Aur Atoll in the 2011 general election, winning an open seat.

[5] Casten Nemra formed a coalition to became President of the Marshall Islands on 4 January,[18] being selected by the legislature with a margin of one vote.

[19] She later said that she did not want to serve in Nemra's ministry because he gave preference to "prominent traditional leaders" over the rest of the coalition that elected him.

[32] Heine implemented a policy within her government that issues were to be addressed by the cabinet collectively instead of unilaterally by individual ministers, and that decisions were to be made based on data instead of social pressure.

She accepted that she would be routinely accompanied by bodyguards and that her husband would have to do their shopping, but she chose not to move to a different house or drive a government car.

[36] Heine was involved in the creation of the Pacific Women Leaders Coalition in 2017 as a means for female politicians in the region to collaborate on gender issues and other causes.

[37] She supported the creation of the government-sponsored Miss Marshall Islands pageant, believing it to be a path for women to adopt leadership positions.

[39] Following a 2017 Marshallese study that found a correlation between poverty and stunted growth in children, Heine successfully requested funding for a childhood development program from the World Bank.

[46] A later investigation by the United States government found that two prospective investors had bribed several officials to support the motion, and that its failure prompted discussion of "revenge".

[51] Heine was reelected to the Nitijeļā in the 2019 general election, winning a close race against a challenger, Justin Lani.

[38] Many of Heine's allies were unsuccessful in their reelection campaigns, losing her the support she needed in order to maintain her government.

[53] She was critical of how Kabua handled renegotiation of the Compact of Free Association with the United States, leading a group who accused him of rushing the process and failing to adequately address climate change and the history of American nuclear testing on the islands.

[57] When the COVID-19 pandemic first affected the Marshall Islands in August 2022, Heine proposed repurposing school buses for public transportation to counter higher taxi fares, eliminating the $5.00 hospital fee, reducing medicine prices, and providing free shipping transportation between islands for citizens.

The first was in regard to limited food and fuel on Kili Island, which had been depleted following the bankruptcy of the Bikini Resettlement Trust Fund.

[66][67] Over the following months, Heine toured the Marshallese populations that faced lasting effects from 20th century nuclear testing conducted by the United States.

[70] Heine has expressed concern that coastal erosion poses a national security risk for the Marshall Islands.

[71] She rejects overseas relocation programs for Marshallese citizens affected by climate change[72] and has criticized the media for its "drowning Pacific Islands" messaging.

[77] In response to high travel prices to and from Micronesia, Heine has suggested that leaders in the region "break up the United Airlines monopoly".

[80] Heine considers violence against women to be one of the most pressing issues in the Marshall Islands and advocates the creation of safe houses for victims to stay.

Other issues she has said are priorities as of her second term include improving energy infrastructure, expanding health services, implementing desalination to improve the water supply, raising the minimum wage, protecting workplace equality for women, expanding the fishing industry, and promoting government transparency.