Ströbele made his school exam abitur in Marl (Westphalia). Then he studied law in Heidelberg and Berlin (at the Free University of Berlin). He has been a lawyer in Berlin (until 1990 West-Berlin) since 1969. He was involved in the student revolt of 1968. He was one of the lawyers of the Rote Armee Fraktion (RAF) terrorists in the Stammheim trial.
From 1970 to 1974 he was member of the Social Democratic Party of Germany. Later he was one of the founders of the "Alternative List for Democracy and Environmental Protection," which later became the Berlin section of the Green Party of Germany.