A native of Rotterode, Thuringia, Hellmuth Mäder joined the Army in 1936 and, by September 1939, was serving as a junior officer with the 34 Infanterie Division.

In the spring of 1940, Oberleutnant Mäder commanded the 14th Company of the Infanterie-Regiment 522 in the newly formed 297 Infanterie Division, which was not deployed in the Western campaign.

In late 1940, he was appointed commander of the III Battalion / Infanterie Regiment 522 and served in that post during the opening phase of Operation Barbarossa.

When the Soviets launched their 1944 summer offensives, he returned to the front, having responsibility for organizing the defense of a vital railway junction at Šiauliai, between Königsberg and Riga.

He led it through the Ardennes offensive, and when, in early 1945, the brigade was expanded to become the Führer Grenadier Division, the promoted Generalmajor Mäder was put in command.

In 1974, he was arrested, convicted, and sentenced to two years imprisonment for money he embezzled in his position in the Bundeswehr, as well as for inconsistencies in his expense reports.