He graduated from Dartmouth College in 1838, and received a master's degree in 1841.

Barrett studied law, first with James Crocker of Buffalo, New York and later with Charles Marsh.

In 1840 Barrett began to practice law in Woodstock as Marsh's partner.

[2] From 1848 to 1849 Barrett practiced law in Boston, and upon returning to Woodstock he formed a partnership with Andrew Tracy and Julius Converse.

[4] In 1857, by now a Republican, Barrett was appointed to the Vermont Supreme Court, where he served until 1880.