As an amateur cyclist Ernst Nievergelt won the 1935 edition of the Zürich Championship to earn himself a place on the Swiss Olympic team. One year later at the Berlin Games, Nievergelt won bronze in the road race, finishing less than a second behind the winner Robert Charpentier. Two more Swiss riders finished in the top 14 places in the road race, resulting in Nievergelt also winning silver in the combined team placings. After the Olympics he turned professional, with his biggest victory coming in 1938, winning the ninth stage of the Tour of Germany. In 1939 Nievergelt had multiple podium places before his cycling career was ended by the outbreak of war.