Between 1950 and 1971, Koch appeared in more than 65 films. She had numerous leading roles in the German cinema of the 1950s and 1960s. In the 1954 American thriller
Night People, she appeared in a supporting role alongside
Gregory Peck. Koch also had major roles in the Hollywood films
Four Girls in Town and
Interlude, both released in 1957. She remains perhaps best known internationally for
Sergio Leone's 1964 production
A Fistful of Dollars, which showcased her with
Clint Eastwood as a civilian tormented by ruthless local gangsters, torn between her husband and child and the villains. In Germany, she was probably best known for her many years of participation as one of the regular panelists in the highly popular TV game show
Was bin ich?, the German adaption of the American TV show ''
What's My Line?'', which ran from the 1950s until 1988 and achieved ratings of up to 75% at its peak. In 1971, she resumed the medical studies she had broken off in the early 1950s to become an actress. In 1974, she earned her degree and practiced medicine until 1997 as a specialist for
internal medicine in Munich. Also in 1974, she was one of the initial hosts of Germany's pioneering talk show
3 nach 9 (
Three After Nine), for which she was awarded the
Grimme-Preis, one of the most prestigious awards of the German television industry. She also hosted other television shows and had a medical advice program on
Bayern 2 radio from 2000 to September 2025. == Personal life ==