Upon his return to Singapore, Jayakumar took on a lecturing position in the Faculty of Law at the National University of Singapore from 1964 to 1981, assuming the position of Dean of the Faculty in 1974.
Sekembalinya ke Singapura, Jayakumar mengambil posisi ceramah di Fakultas Hukum di National University of Singapore 1964-1981, dengan asumsi posisi Dekan Fakultas pada tahun 1974.