Joseph Haslet, born in Milford, Delaware, developed early leadership skills under the guardianship of Chief Justice William Killen. He honed his expertise through an apprenticeship in watchmaking and later transitioned into public service. Haslet spent significant time managing state defense initiatives, particularly during the War of 1812, where he organized and funded the militia, and oversaw fortifications. His governance was marked by a focus on state-federal cooperation, despite challenges from the Federalist-dominated legislature.

Joseph Haslet's political identity is marked by a calculated approach to regional industrial interests, as evidenced by his unexpected legislative stances on environmental regulations. His governance style is characterized by a tension between advocating for state-level militias and emphasizing cooperation with federal defense initiatives. Haslet's rhetoric often highlights the necessity of state support for national initiatives, revealing a nuanced understanding of federalism.