[2] He was raised and educated in Manchester, and at age 19 began the study of law with Richard Skinner.

[2] In 1831, he received the honorary degree of Master of Arts from Middlebury College.

[3] In the 1820s and 1830s, Isham was active in the Vermont Militia and served as inspector of the 2nd Division, which was headquartered in Manchester.

[4] In 1848, the Vermont General Assembly appointed Isham state bank commissioner, succeeding Carlos Coolidge, and he served until 1850.

[5] In 1851, Isham was appointed an associate justice of the Vermont Supreme Court.