Following his return to Lebanon Rizk taught courses on
urology at the Saint Joseph University from the mid-1960s.
Cabinet posts Rizk was named as minister of social affairs and labour and minister education on 9 December 1976 to the
cabinet led by
Salim Hoss. Rizk was also appointed minister of oil and industry on 20 December 1978 in a cabinet reshuffle. He succeeded Selim Hoss in the post who had been serving as minister of petroleum and minister of industry since 9 December 1976. Rizk's term in all offices ended on 16 July 1979 when a new cabinet was formed by Selim Hoss.{{cite journal|year=1979 Rizk was named as the minister of industry and petroleum in 1992 and served in the
cabinet led by
Rafic Hariri until 1995.{{cite book|author=Ward Vloeberghs|year=2015|title=Architecture, Power and Religion in Lebanon. Rafiq Hariri and the politics of sacred space in Beirut|publisher=
Brill|url=https://doi.org/10.1163/9789004307056_010|location=Leiden; Boston ==Personal life and death==