During World War II came his last movies into being as a sound engineer.
The actor and sound engineer Hans Grimm first learned the profession of an electrician and mechanical engineer, but in 1927 he chose an other job and he worked as a sound mixer of movies for Hans Vogt.
His son was the famous child actor Oliver Grimm who took part in numerous movies in the 50s.
Hans Grimm was also active as a director.
Hans Grimm also wrote some screenplays for some of his son's movies like "Wenn der Vater mit dem Sohne" (1955)with his son in a leading role.