After finishing school, Thomas W. Wood worked in a cabinet shop owned by his father. By 1844, he was sketching the surrounding Vermont landscape, and he began to spend his winters in Boston where he studied for a short time with Chester Harding. Wood married Minerva Robinson in 1850, and they built their Montpelier home, Athenwood, to which they regularly returned until their deaths. After several years of painting portraits and doing odd jobs, however, Wood left for New York City in 1852 in search of more important commissions. He made two portrait-painting trips to Canada and one to Washington, D.C. before settling for two years in Baltimore in 1856.
During the summer of 1858 Wood left for Europe, spending a year in England, France, Italy, and Switzerland. He returned to take up residence in Nashville Tennesssee, with occasional trips to Minnesota and Montpelier. He then moved to Louisville KY in 1862, remaining four years. After the Civil War, he made the decision to return to New York in an attempt to live off his genre paintings without any "pot-boiling" portrait work.
In New York, Wood became active in the leading artistic organizations, serving as president of the American Water-Color Society during the decade beginning in 1878, and helping found the New York Etching Club. He taught briefly in the National Academy Schools and was elected to the Council for a three-year term in 1876, followed by twelve years as vice president and eight as president of the Academy. Wood took up portraiture again around 1890 and concentrated on making copies from the Old Masters for his Wood Art Gallery, which opened in Montpelier in 1895. Much of the rest of his life was spent painting copies and securing contemporary American works for the gallery.