Koçyiğit decided to venture into cinema in 1963 after she was the runner-up in a beauty contest organized by the magazine Ses (literally: Sound). Her debut film was the 1964 Susuz Yaz (Dry Summer), which went on to win the Golden Bear Award at the 14th Berlin International Film Festival. This honor was the first of its kind ever bestowed upon a Turkish movie. Derman, a film she starred in was the first Turkish film that played in five continents. Kurbağalar, another of her famous films was the first Turkish movie that was sold to international televisions. She received the distinction of "Turkish state artist" in 1991.
Koçyiğit holds the distinction of being the Turkish Actress of having won the most national and international awards and is probably, the most recognised face of the Turkish silver screen. Her movies between 1965 and 1974, her golden period, constantly captivated movie audiences. She was recognizable in many countries like Algeria, Greece, Iran, Lebanon.
She married in 1968 to Selim Soydan, then a Fenerbahçe S.K. footballer. The couple has a daughter named Gülşah.
