From 1990 to 1992, he served as foreign minister from when he left office for a few months following the general elections in 1992[4] and was temporarily replaced by Nasri Maalouf in the post.
[5] It was Boueiz who participated in a first official meeting with the PLO's Farouk Qaddumi, head of the group's political department, in mid-May 1991 after a long period.
In 2003, Boueiz was appointed environment minister to the cabinet led by Rafic Hariri, replacing Michel Musa in the post.
[10] On 7 September 2004, he resigned from office protesting the constitutional amendment to extend the term of Émile Lahoud as president.
[18] On the other hand, Boueiz was skeptical about the peace accord signed by Israel and the PLO in 1993, and argued that Palestinian refugees should not settle in Lebanon due to sensitive demographic balance between native Christians and Muslims in the country.