 In 1961 he passed the "First", in 1965 the "Second Legal State Examination", and started working as a lawyer in Hamburg.After joining the "Social Democratic Party of Germany" (SPD) in 1964, Klose became a member of the Hamburg Parliament ("Hamburgische Bürgerschaft") in 1970, where he was vice chairman of his faction.Two years later he became first chairman of the SPD parliamentary group.