1965, agent noun from re-enact (v.). Specifically, "one whose hobby or profession is to embody accurate historical presentation" by 1984, American English.
Entries linking to re-enactor
re-enact v.
also reenact, "enact again," 1670s, from re- "back, again" + enact. Originally especially of legislation; the general meaning "to perform again, reproduce" is attested by 1854. Related: Re-enacted; re-enacting.