Allen graduated magna cum laude in 1971 from Harvard Law School, where he served as President of the Harvard Law Review. After clerking for the U.S. Supreme Court in the 1971 Term, he joined Hogan and Hartson, engaging in a wide-ranging trial and appellate litigation practice, including serving as Chair of the Firm’s litigation practice group for 15 years. He also served as Chair of the D.C. Court of Appeals’ Board on Professional Responsibility and of the D.C. Circuit’s Board on Admissions and Grievances and served on the Board of the Washington Council of Lawyers for 16 years. After retiring from private practice, Allen and his wife Susan served as emergency foster parents for numerous neglected and abused children in the Montgomery County court system before falling in love with and adopting Ceci, who arrived in their family in 2005 when she was two months old. Susan and Allen have two wonderful older daughters, ages 33 and 29, as well.