Tamir joined the General Zionists party, and became its general secretary. Between 1965 and 1969 he was a member of the Tel Aviv directorate as head of the Liberal Party faction (a merger of the General Zionists and the Progressive Party). In the 1965 elections Tamir was also elected to the Knesset as member of Gahal, an alliance of the Liberal Party and Herut. Yosef retained his seat in the 1969 election, and again in the 1973 election, before which Gahal had become Likud.
After being elected to the Knesset for Likud again in the 1977 election, Tamir broke away from the party and joined the newly formed Shinui, a centrist liberal party. However, he soon left his new party and spent the rest of the Knesset session as an independent MK. He was not returned to the Knesset in the 1981 elections.
Environmental activism
During his lifetime Tamir founded several environmental organisations:
Council for a Beautiful Israel (1968)
Non-factional Committee for Ecology (1970)
Life and Environment Organization (1975)
Israel Economic Forum on the Environment (1991)
He also launched the environmental journal Green Blue and White.
Tamir represented the Knesset at the First United Nations Conference on the Environment of Man in Stockholm in 1972, and was the Likud representative in the Knesset delegation that visited the United States Congress in 1975 and the German Bundestag in 1977.
Tamir won several prizes for his environmental activism, including the United Nations Environmental Prize and a Knesset Prize for "Achievements in the Area of Environmental Quality".
