In the years 1938-1939, he was active in "HaHalutz" and the Young Zionists organization in Europe. In 1940-1942, he was on a political mission in England and Constantinople. In 1943-1945, he was in contact with the anti-Nazi Jewish Underground in Europe, and headed the Haganah's delegation to the United States as part of his position in the Political Division of the Jewish Agency. In 1947-1948 he managed the U.S. division in the Ministry of Foreign Affairs. In 1951-1952 he was an envoy and delegate in Washington. In the years 1952-1965, he was a general administrator in the office of Prime Minister David Ben-Gurion. In 1964-1966 he was Chairman of the Israeli-American Committee for the Desalination of Seawater, as well as Chairman of the board of directors of the Israel Museum. In the twenty-eight years of his tenure as Mayor of Jerusalem, the city grew, expanded and developed in all areas. The Jewish Quarter of the Old City was restored; eleven new neighborhoods were built; the city's parks and streets multiplied, grew and expanded. The city became a bustling hub of work and creativity. Many tourists visit its sites.
In 1977, he was awarded an honorary doctorate degree for all his work for Jerusalem and for the welfare of the State of Israel. Teddy Kollek died on the 12th of Tevet, 5767, January 2nd, 2007