He read law with Isaac Fletcher, attained admission to the bar in 1827, and practiced in Wells River, Vermont.
[1] Having decided early on a legal career, Underwood attended the academy in Royalton to prepare for a university education, and taught school to help pay his expenses.
[3] After receiving his degree, Underwood studied law with Isaac Fletcher in Danville, and attained admission to the bar in 1827.
[2] His practice became successful after his return to Wells River, and Underwood became one of Vermont's most prominent corporation attorneys, with his specialty being railroad rights of way and construction.
[3] In 1867, Underwood was appointed federal Register in Bankruptcy for Vermont's 2nd congressional district, and he served until his death.