One of Trask's contributions to the Hawaiian sovereignty movement was her founding of Na Koa Ikaika o Ka Lāhui Hawaiʻi, a native Hawaiian non-governmental organization[1] focusing on cultural, social, and economic development, education, health, housing, land entitlements, energy, and water issues.

[2] Outside of Hawaiʻi, Trask has worked with the United Nations to aid indigenous people from around the world seeking independence.

Her uncle, David Trask Jr., was a senator, a state representative, and a leader of the Hawaii Government Employees Association.

In 2016 she ran for the Big Island OHA Trustee position on the grounds that the Office of Hawaiian Affairs needed to be more accountable to its beneficiaries.

Mililani Trask also holds eighteen years of experience with ceded Hawaiian land trusts and affordable housing.