Kammala jumla mai zuwa: Farawa a 1948, Henkin ya yi aiki a ofishin Majalisar Dinkin Duniya na Ma'aikatar Harkokin Wajen Amurka, inda ya kasance ɗaya daga cikin mutanen da ke da alhakin Yarjejeniyar da ta shafi matsayin 'yan gudun hijira a 1951, yarjejeniyar da ta kafa yarjejeniyar da aka amince da ita a duniya game da abin da ke zama' yan gudun hijira kuma ya kafa bukatun ga ƙasashe don ba da mafaka ga mutanen da aka zaba. Ya bar Ma'aikatar Harkokin Waje a shekarar 1956 don koyarwa na shekara guda a Jami'ar Columbia kan batun kwashe makaman nukiliya wanda ya zama batun littafinsa na 1958 "Arms Control and Inspection in American Law". Ya koyar a Jami'ar Pennsylvania farawa a 1958, ci gaba da aikinsa da aka buga a matsayin "The
Berlin Crisis da Majalisar Dinkin Duniya" a 1959 da kuma littafin "Disarmament: The Lawyer's Interests", wanda aka saki a 1964.