Katsav joined the Likud party and at the young age of 24 was elected the mayor of Kiryat Mal'akhi, the small town in which he was raised. He was subsequently elected as a Member of the Knesset in 1977. Under the governments of Begin and Yitzhak Shamir, Katsav served as the deputy Minister of Construction and Housing (1981–83). He then served as the Minister of Labor and Welfare during the national unity government which served in the years 1984-88. During 1988-92 he served as the Transportation Minister under Yitzhak Shamir, and under Benjamin Netanyahu's government (1996–1999), he served as Deputy Prime Minister and Minister of Tourism.
The public positions filled by Katsav include the following: Chairman of the Iranian Immigrants Organization; Chairman of the commission to determine higher education tuition; and Member of Ben-Gurion University Board of Trustees.