He was a member at the minor planet studies group at Astronomisches Rechen-Institut between 1947 and 1950, and later became "Oberobservator" or chief-observer at Heidelberg Observatory until his retirement in 1957.
[4] Reinmuth obtained more than 12,500 precise astrometric measurements of minor planets' positions on photographic plates, an enormous accomplishment before computer-based assistance existed.
He also discovered several large Jupiter trojans including 911 Agamemnon, 1143 Odysseus, 1172 Äneas, 1173 Anchises, 1208 Troilus, 1404 Ajax, 1437 Diomedes and 1749 Telamon.
The main-belt asteroid 5535 Annefrank, which he discovered in 1942 during World War II, was later visited by the Stardust spacecraft in 2002.
[5] His lowest numbered minor planet discovery is 796 Sarita, an asteroid from the middle region of the main-belt.