In 1957 he became a coach at Casa Centrală a Armatei, now CSA Steaua București. He also took responsibility of the national foil teams. Under his guidance, the men's team won Romania's first world title in fencing at the 1967 World Fencing Championships in Montreal, Ion Drîmbă won the gold medal in foil at the 1968 Summer Olympics in Mexico City and the women's team won the world title at the 1969 World Fencing Championships in Havana. For his accomplishments Chelaru was named "honoured coach" ("antrenor emerit") in 1968.