Tsochatzopoulos was born in Athens on December 19 of 1939 but spent his formative years in Thessaloniki. He studied civil engineering and economics in Munich and early on became a close political ally of Andreas Papandreou.
Tsochatzopoulos served in the cabinet of most Papandreou governments except for a brief period when he was Secretary of the Central Committee of PASOK:
- As Minister of Public Works (1981 - 1984)
- As Minister of Labour (1985)
- As Minister of Public Order (1989)
- As Minister of Transportation (1989 - 1990)
- As Minister of the Interior (1993 - 1994 and 1995 - 1996)
- As Minister of Defence (1996 - 2001)
- As Minister of Development (2001 - 2004)
Tsochatzopoulos was acting PM during Papandreou's illnesses and twice sought the leadership of PASOK losing to Constantine Simitis.
In June 2010, he came under investigation for possible illegal financial activities after it became known that he and his wife owned expensive properties in the centre of Athens and had extensive links to offshore companies.
He was found guilty of all charges on October 7 of that same year.
Tsochatzopoulos is in his second marriage and has two children with his first wife.