Stancho Ivanov was brought up living in poverty, having to graze other people’s cattle as a boy. Ivanov loved to fight in the small Bulgarian village where he lived, with someone suggesting he should take up wrestling in the nearby city of Stara Zagora. From there he became a multiple-time national freestyle champion and began representing the Bulgarian national wrestling team in the late 1950s. In 1958 he won bronze in the 62 kg at the World Cup in Sofia, before winning silver in the 63 kg at the World Championships in Tehran. These performances earned Ivanov a place on the Olympic team for the 1960 Roma Games, where he won silver in the featherweight class, losing to Mustafa Dağıstanlı (TUR) in the final.
Ivanov continued to have good results, including a bronze in the 63 kg at the 1963 World Championships in Sofia. One year later he returned to the Olympics, where history repeated itself with him winning his second silver at the Games. The format at the Tokyo Games was different than in Roma, with Ivanov drawing his final bout with Nodar Khokhashvili (URS), and Khokhashvili losing to the gold medallist Osamu Watanabe (JPN), resulting in Ivanov winning silver based on a lower bodyweight. Only six months prior Ivanov had been on an infectious disease ward in hospital after suffering with hepatitis. The following year, he once again became the “nearly man” when he won another silver at the 1965 World Championships in Manchester.