Following a period of military service in Algeria, Deguelt returned to France, and was offered the chance in 1960 to sing for Monaco in the fifth Eurovision Song Contest, held in London on 29 March.

Deguelt's song "Ce soir-là" ("That Night") proved popular with the juries, finishing in third place of the 13 entrants.

[1][2] Deguelt returned to Eurovision, again representing Monaco, in 1962 with the song "Dis rien" ("Say Nothing").

[3][4] Deguelt is one of five acts in Eurovision history (alongside Cliff Richard, Katja Ebstein, Chiara Siracusa and Zeljko Joksimovic) to have finished second and third without having won.

He continued to tour and perform on the nostalgia circuit throughout the Francophone world until his death.