His elder brother Dieter Prochnow, born 1939, is also an actor. Together, the brothers appeared in The Man Inside where Jürgen played the leading role and Dieter a small supporting role.
In the early 1980s, Prochnow was in a relationship with Austrian Actress Antonia Reininghaus who fatally poisoned their Common seven-year-old daughter Johanna in 1987. In 1982, he married actor Jürgen Goslar′s daughter Isabel Goslar, with whom he has two children: a daughter, Mona, and a son, Roman. The couple divorced in 1997. From 2004 to 2014 he was married to Birgit Stein, a German Screenwriter and Actress. Since 2015, he has been married to Actress Verena Wengler.
In 1996, he was a member of the jury at the 46th Berlin International Film Festival.
Prochnow used to divide his time between Los Angeles and Munich. In 2017 he announced that he had sold his house in California and would be moving to Berlin.
