Allen attended Leicester Academy (1809–1811) and Yale College (1811–1812) and studied law.
He was admitted to the bar in 1818 and commenced practice in New Braintree. He returned to Worcester in 1824 and continued the practice of law. He was elected as the Free-Soil Party candidate to Congress (March 4, 1849 - March 3, 1853) and did not seek renomination in 1852.
In 1849 he edited the Boston " Whig," afterward called the "Republican."
After leaving Congress, he resumed the practice of law in Worcester.
He was Chief Justice of the Sufolk County Superior Court (1859–1867). He was a delegate to the peace convention held at Washington, District of Columbia in 1861, in an effort to devise a means to prevent the impending Civil War.
Charles Allen died in Worcester on August 6, 1869. He was interred in the Rural Cemetery.
The home on which he began construction, the Charles Allen House, was completed by his descendants and was added to the National Register of Historic Places in 1980.
Free Soil Party, Republican Party.
In 1827 he was elected a member of the American Antiquarian Society. Allen was a Member of the Massachusetts House of Representatives (1830, 1833, 1835, and 1840). He served in the Massachusetts State Senate (1836–1837).
He was a member of the Northeastern Boundary Commission in 1842.
A judge of the Court of Common Pleas (1842–1845) and a delegate to the Whig National Convention at Philadelphia in 1848. He was a member of the state"s constitutional convention in 1853.