He was educated at Tel Aviv University and Oxford University from which he received a Ph.D. in History. He was a historian at Tel Aviv University from the mid-1970s, serving as head of the School of History from 1982 to 1986. His initial field of study was Spanish history, and his 1983 biography of the former Spanish Dictator, General Primo de Rivera (1923-1930), is still recognized to this day as arguably the most authoritative study on this subject. He later turned his attention to the history of Israel and the Middle East, but not without leaving a legacy of expertise in Spanish inter-war year politics that is still influential to this day. From 1987 until 1991, before he entered politics, he was the first Israeli ambassador to Spain. In 1996 he was elected to the Knesset on Labour's list.
When the One Israel-led government of Ehud Barak took office in July 1999, Ben-Ami became the Minister of Internal Security, responsible for the Israel Police. In August 2000, when David Levy resigned as Foreign Minister during talks with Palestinian leaders in the United States, Barak designated Ben-Ami to be the acting Foreign Minister and he was officially appointed to the role in November 2000.
Ben-Ami remained Foreign Minister and Security Minister until March 2001, when, having won elections, Ariel Sharon took over from Barak. Ben-Ami refused to serve in the Sharon government and resigned from the Knesset in August 2002.
In their report published in 2003, the Or Commission held him responsible for the behavior of security forces during the October 2000 riots in which Israeli police killed 12 Israeli Arabs and one Palestinian, and failed to predict and control rioting which resulted in the death of a Jewish Israeli. The report recommended that Ben-Ami be disqualified from serving as Internal Security Minister in the future. Despite the disqualification, Ben-Ami was not considered to be a hard-liner in Israeli relations with the Palestinians and during his time in the Barak government, he was a political rival of Shimon Peres.
Ben-Ami is currently Vice-President of the Toledo International Centre for Peace (TICpax), which, according to its mission statement, "seeks to contribute to the prevention and resolution of violent or potentially violent international or intranational conflicts and to the consolidation of peace, within a framework of respect and promotion of Human Rights and democratic values."
In April 2008 signed a letter in support of J Street, a new American Jewish lobby organization, advocating peace in the Middle East.
ISRAEL: PM DIRECTS MINISTER BEN-AMI TO CUT SHORT CURRENT ROUND OF TALKS WITH PALESTINIANS.(Ehud Barak, Shlomo Ben-Ami)(Brief Article)
May 22, 2000; (Communicated by the Prime Minister's Media Adviser). Prime Minister Ehud Barak yesterday (Sunday), 21.5.2000, directed Public...