In 1974 Monsels was a tank driver in the Royal Netherlands Army. In 1975 he returned to Suriname from the Netherlands as the country became independent. He became a sports instructor in the Suriname National Army. After the 1980 coup, he received a promotion and became sports chief in the Surinamese army. In 1983, he acted as an intermediary between strongman Dési Bouterse and the exiled former President Henk Chin A Sen. In 1987 he left the Surinamese army and moved to the Netherlands.