Answer
No, Berger has not always driven for Austrian teams in his F1 career. Berger was born in Austria and started his F1 career with a team from his home country, the ATS team. However, after a few years with ATS, Berger moved to other teams, including McLaren, Ferrari, Benetton, and McLaren again. He also drove for the Austrian team Jaguar for a brief period of time.