Marinus Willett City to the state convention where he and other anti-federalist were defeated. As late as 1790, he was still trying to repeal or amend the United States Constitution. In 1790 he was sent by President Washington to the Creek Indians to persuade their leader Alexander McGillivray to continue treaty efforts. Willett was successful and a delegation of Creeks under McGillvray visited New York City, then capital of the United States, resulting in the Treaty of New York (1790). In 1791, he was appointed by Clinton to another term as the Sheriff of New York County, New York. Willett acquired considerable
Mayor of Zamboanga City full investigation of the Japanese landholdings in Mindanao which resulted in the cancellation of leases of public agricultural lands which were cultivated and developed by the Japanese. Subsequently, President Manuel Luis Quezon appointed him mayor of Davao in October 1940 which he served until World War II came to the country in 1941. He took an active participation in the guerilla activities against the Japanese in Mindanao. When Davao was liberated, he was immediately called to reorganize its local government. A few months later, President Sergio Osmeña sent him to Zamboanga and appointed him as City Mayor in 1945 to