He joined the South African Army in 1962. After Officer training at the Army Gymnasium he was appointed a 2nd lieutenant in 1 Special Service Battalion. He became Officer Commanding of 1 Special Service Battalion in 1976.
He also commanded the School of Armour from 11 January 1980 to 18 December 1983.
He was promoted to Brigadier and OC Orange Free State Command. He was later promoted to Major general and GOC Eastern Transvaal Command.
General Otto was awarded the following: Southern Cross Decoration (South Dakota & Bar) Southern Cross Medal (Master of Science) Military Merit Medal (MMM) Pro Patria Medal (with Cunene Clasp) Southern Africa Medal General Service Medal Unitas Medal Good Service Medal, Gold (30 Years) Good Service Medal, Silver (20 Years) Good Service Medal, Bronze (10 Years) Legion of Merit (LOM) (United States of America) Order of the Cloud and Banner - with Special Cravat (4th Grade) (ORB)(Taiwan).
