1945 – Allen was born in Portland, Maine on April 16, 1945.
1968 – Married Diana Bell.
1970 – Attended Bowdoin College and later transferred to Wadham College in the University of Oxford after he won a Rhodes Scholarship.
1974 – Earned his degree in law at the Harvard University.
1975 – Became a lawyer and worked as a staff member for Governor Kenneth M. Curtis, for the senator Muskie and for the Mayor of Portland, Maine.
1997-2006 – Elected as a Democratic member of the United States House of Representatives, representing the 1st District of Maine.