Chess historian Edward Winter wrote, "He dedicated his life to chess-playing, touring, writing, teaching and analysing.

Despite only occasional participation in first-class events, he scored victories over all the leading masters of the time (Anderssen, Blackburne, Chigorin, Mackenzie, Mason, Paulsen, Steinitz and Zukertort).

He also acquired world renown as an unassuming showman who gave large simultaneous displays and blindfold séances, invariably producing a cluster of glittering moves.

Rosenthal won the Café de la Régence championship in 1865, 1866, and 1867 in Paris, and became the strongest French chess player.

In 1880, he won in Paris the first unofficial French Chess Championship (ahead of Albert Clerc and Jules Arnous de Rivière).