​​Heinz Semmelbeck was born in Niederhochstadt on 27 August 1908, the son of Heinrich and Karoline Semmelbeck. Two months after passing his A levels at the Humanistisches Gymnasium in Ludwigshafen in March 1927, he began studying law. Semmelbeck studied at the universities in Königsberg, Munich, and Erlangen. In Erlangen he passed the first state law examination in February 1932. He then worked as a legal trainee in various local and state courts and in district offices. After passing the second state law examination, he worked as a court assessor in Frankenthal in early 1936. In the same year he joined the Sturmabteilung (SA). On 1 May 1937, Semmelbeck was finally admitted to the NSDAP after the general admission ban was lifted. His membership number was 4929292, and he belonged to the Frankenthal branch of the Saarpfalz district.

​On 8 November 1937, he married Maria Martha Gehra and the couple had two sons. Less than a year after their marriage, Semmelbeck received his doctorate in law from the University of Erlangen.

​In June 1940, he began his military service in the reserve of the Sanitätsersatzdienst (combat medic reserve organisation) in Frankfurt. He was then deployed with the 1st Grenadier Regiment 1021 of the Wehrmacht on the French Channel and Atlantic coasts. On 6 July 1944, Semmelbeck was killed at St. Germain when a shell fragment penetrated his helmet. Semmelbeck rests at the La Cambe War Cemetery in Block 49, Row 1, Grave 5.​