Peter Heilmann lived with his parents and three siblings in Berlin. In 1932 he started attending the Protestant Graues Kloster high school, but had to leave in 1938 as a “1st grade Mischling” (half-breed). His father, the SPD politician Ernst Heilmann, was arrested in the spring of 1933, and was murdered in Buchenwald concentration camp in early April 1940.
The Heilmanns experienced the persecution of Jews among their family and friends. Peter Heilmann, his mother Magdalena, and his sister Eva were involved in a range of activities to support people in hiding. They took people at risk into their home in Berlin-Kreuzberg, including the Jewish couple Eva and Martin Deutschkron and the young escapees Gerd Ehrlich and Ernst Schwerin. Else Behrend-Rosenfeld also found refuge with the Heilmanns. Peter Heilmann obtained a postal identity card for her in the name of “Martha Schröder.”
Peter Heilmann himself was drafted into the Organisation Todt (OT) in the fall of 1944 and interned in an OT camp outside Zerbst. He managed to escape in February 1945. He returned to Berlin, where his girlfriend Hella Gorn hid him until the end of the war.