Erkki Penttilä took up wrestling in 1942 and made his international début at the 1954 World Championships, where he was eliminated after two rounds in freestyle lightweight. Switching back and forth between the freestyle featherweight and lightweight classes his entire career, Penttilä had his best results as a featherweight, winning Penttilä Olympic bronze in 1956 and coming in fourth and xith at the 1957 and 1959 World Championships respectively. As a lightweight, Penttilä competed at the 1965 World Championships and 1966 European Championships, but was eliminated from competition early. Domestically, Penttilä won 12 Finnish titles, all of them in freestyle lightweight in 1954-64 and 1966. After retiring in 1967, Penttilä worked as a farmer, raising broilers and pigs. At the end of the 1960s, he was also briefly the coach of the Finnish national freestyle team.