Voog began climbing in 1959, primarily in the Dolomites range of the Alps. Her early climbs included Wildspitze (1959), Königspitze (1961) and Cinque Torri (1963). She achieved national fame on 4 September 1964, when she became the first woman to ascend the Eiger's north face, which she climbed via the Heckmair route with Werner Bittner. The Eiger was one of numerous alpine ascents she made in 1964, others included Predigstuhl, Gurrwand, Torre Venezia, Torre Trieste, Kleinste Zinne and Kleine Zinne, Monte Civetta, Marmolada, and Piz Lasties.