In 1964, Ikeda married Turkish biochemist Emel Ardor, whom he met and followed to Turkey. He was naturalized and adopted the Turkish name Gündüz. He became associate professor in 1965 and full professor in 1966. With permission of the university, he went 1968 to the Middle East Technical University (METU) in Ankara as visiting professor for one year. However, following the end of his term, he was offered a permanent post as full professor, which he accepted upon the proposal of the mathematician Cahit Arf, whom he had known since his early years in Turkey.