A pupil of the Neapolitan tenor Fernando De Lucia (1860–1925), Thill made his operatic debut at the Paris Opéra in 1924, and he continued to appear there and at the Opéra-Comique for several decades, undertaking a busy schedule of performances.

Chronologically, Thill's operatic repertoire ranged from Gluck to Puccini and embraced works by Gounod, Massenet, Berlioz, Meyerbeer, Wagner, Verdi and Leoncavallo, among others.

The finest of his 78s, dating from 1927 to circa 1940, display the gleaming tone of his voice at its superlative best, as well as demonstrating his spotless taste, stylish phrasing and pellucid diction.

Thill also appeared in several film clips and French-language motion pictures, including Louise (1939), based on Gustave Charpentier's opera.

Privately, Thill, while a dedicated musician, enjoyed a convivial off-stage lifestyle, and he later blamed his propensity to burn the candle at both ends for shortening the span of his vocal prime.