"one who works or endeavors to make converts," 1811, agent noun from proselytize.
Entries linking to proselytizer
proselytize v.
1670s, "to make proselytes," from proselyte + -ize. The transitive sense of "convert (someone) to some religion, doctrine, etc.," is by 1796. Related: Proselytized; proselytizing. The earlier verb form was simply proselyte (1620s).