After the war, he fought with the Freikorps in the Baltics and in 1920 was accepted by the Reichswehr, where he served in a number of posts in the infantry.

Heidrich was transferred to the staff of the 7th Air Division, but then left the Luftwaffe to lead the 514th Infantry Regiment in the Battle of France.

Starting 12 July 1943, the 1st Parachute Division was deployed to Sicily to counter the Allied invasion of the island.

The 1st Parachute Divisions toughest fighting came after the Allied landings on the Italian mainland, particularly in the three battles of Monte Cassino.

When he was released from captivity in the summer of 1945, General Richard Heidrich, who had never recovered from his wounds, did not have long to live and died on 22 December 1947 at the age of just 51 in the Hamburg-Bergedorf (another source states Hamburg-Bahrenfeld) care hospital (Versorgungslazarett).