Van Dyke entered political life in 1774 as a member of the Boston Relief Committee in Delaware. He then was a member of the Delaware Constitutional Convention of 1776 and served in the State Council for two years beginning with the 1776/77 session. That same year he was appointed as Judge of Delaware's Admiralty Court, and on February 22, 1777 he was elected to the Continental Congress to replace John Evans who had declined to serve. He would remain in Congress through 1781 and signed the Articles of Confederation for Delaware. For five sessions, from 1778/79 until he became President of Delaware in 1783, he served in the State House and was the Speaker in the 1780/81 session.