He studied law, international relations and economics at the Hebrew University of Jerusalem, and obtained his Bachelor of Laws in 1958. Between 1958 and 1960, having been drafted into the Israeli Defense Forces, he served in the office of the Financial Advisor to the Chief of Staff. Upon discharging his service he returned to the Hebrew University, where he completed his doctoral dissertation with distinction in 1963. Simultaneously he began work as an intern at the Attorney General's office. When the Attorney General began dealing with the trial of Adolf Eichmann, Barak, being a Holocaust survivor, preferred not to be involved in the work. He was transferred to the State Attorney's office to complete his internship at his request. Upon completing his internship he was recognised as a certified attorney.