In 1890, Allen worked as a farmer in Botetourt County. After graduating, he practiced law. In May 1895, Allen was elected
commonwealth's attorney of Botetourt County. He was re-elected in May 1899 and November 1903. He served in that role for 16 years. Allen served as a member of the Virginia House of Delegates in 1901. He served as chairman of Botetourt County's democratic committee for 15 years. ==Personal life==