They were artistes whose stage appearance, resplendent in evening dress (generally white tie), contrasted with the cloth-cap image of most of their music-hall contemporaries.
According to Michael Kilgarriff, it was J. J. Poole, manager of the South London Music Hall, who first described the performer George Leybourne as "a Lion of a Comic".
Victorian fashion then led to the use of the French words, lion comique, which in turn became a generic term for all performers with an imposing appearance and personality.
[1] The songs the lions comiques sang were "hymns of praise to the virtues of idleness, womanising and drinking",[2] perhaps the most well known of which is George Leybourne's "Champagne Charlie".
The lion comique deliberately distorted social reality for amusement and escapism.