Timothy Howe was born in Livermore, Maine, on 24th February, 1816. After graduating from the Maine Wesleyan Seminary, Howe studied law and was admitted to the bar in 1839. Howe worked as a lawyer in Readfield, Maine, before moving to Green Bay, Wisconsin, where he became a supreme court justice (1850-53).

A member of the Republican Party, he was elected to the 37th Congress in 1860 and became a leading figure in the group that became known as the Radical Republicans. Howe strongly supported the Freeman's Bureau, the Civil Rights Bill and the Reconstruction Acts. After the American Civil War Howe clashed with President Andrew Johnson and voted for his impeachment in 1868.

Howe served as chairman of the Committee on Enrolled Bills (1862-66), Committee on Claims (1864-70), and Committee on Foreign Relations (1868-70). Timothy Howe died in Kenosha, Wisconsin, on 25th March, 1883.