Endowed with a handsome face and manly figure, he studied the delivery and gestures of the most distinguished advocates in the Forum, especially Q Hortensius, and won universal praise for his grace and elegance on the stage. He especially excelled in comedy. Cicero took lessons from him. The two often engaged in friendly rivalry to try whether the orator or the actor could express a thought or emotion with the greater effect, and Roscius wrote a treatise in which he compared acting and oratory. Q. Lutatius Catulus composed a quatrain in his honour, and the dictator Sulla presented him with a gold ring, the badge of the equestrian order, a remarkable distinction for an actor in Rome, where the profession was held in contempt.
Like his contemporary Aesopus, Roscius amassed a large fortune, and he appears to have retired from the stage some time before his death. In 76 BC he was sued by C. Fannius Chaerea for 50,000 sesterces, and was defended by Cicero in a famous speech.
By the Renaissance, the reputation of Roscius formed the cynosure and paradigm for dramatic excellence. When Thomas Nashe wanted to praise Edward Alleyn as the best actor of his generation, he called Alleyn a Roscius (Pierce Penniless, 1592); John Downes titled his history of Restoration drama Roscius Anglicanus (1708). The African American actor Ira Aldridge, who was born in New York in 1807 and died in Lodz, Poland in 1867, and one of the finest Shakespearean actors of his age, was known as 'The African Roscius'.