early 13c., from Old French persone "human being, anyone, person" (12c., Modern French personne) and directly from Latin persona "human being, person, personage; a part in a drama, assumed character," originally "mask, false face," such as those of wood or clay worn by the actors in later Roman theater. OED offers the general 19c. explanation of persona as "related to" Latin personare "to sound through" (i.e. the mask as something spoken through and perhaps amplifying the voice), "but the long o makes a difficulty ...." Klein and Barnhart say it is possibly borrowed from Etruscan phersu "mask." Klein goes on to say this is ultimately of Greek origin and compares Persephone.
Of corporate entities from mid-15c. The use of -person to replace -man in compounds and avoid alleged sexist connotations is first recorded 1971 (in chairperson). In person "by bodily presence" is from 1560s. Person-to-person first recorded 1919, originally of telephone calls.