Serlin attended a yeshiva in Białystok, studied law at the University of Warsaw and became a lawyer in 1929. He was in the Zionist movement in Poland. He was the personal secretary of Nahum Sokolow in 1930. In 1933 he emigrated to Palestine to work in Tel Aviv as a lawyer. In 1948 he was a member of the Provisional State Council (Hebrew מועצת המדינה הזמנית, Moetzet Hamedina HaZmanit )
For the first four terms of office from 1949 to 1961 he was a member of the Knesset of the General Zionists. From 1961 to 1965 he was Member of the Knesset the Miflaga Liberalit Jisra'elit. From 1965 to 1974 he was member of the Knesset of Gachal. 1952/53, he was Minister of Transport and 1953 to 1955 he was Minister of Health.