A member of the gens Matia, he belonged to the party of Caesar, and helped Cicero in his relationship with Caesar in 49 and 48 BC. After the murder of Caesar, Matius, a dedicated Caesarian, warned of potential for grave repurcussions including possible rebellions in Gaul or revolts of Caesar's legions. When Octavian came to Rome, Matius became one of his close associates. Matius and Octavian managed the July 44 games honoring the recently assassinated dictator. An exchange of letters between Cicero and Matius later in 44 has been preserved (Letters to Friends, 11.27 f.).
A Gaius Matius (PW 2) is recorded as a friend and assistant of Caesar Augustus, an eques who wrote three volumes on gastronomy (Columella credits him with "mincemeat à la Matius" (minutal Matianum)), and was said by Pliny the Elder to have invented the clipping of shrubbery. It is unclear however if this is the same person, or a later generation.