Leisy will succeed Erik Altemus in the role. Altemus will play his final performance Dec. 5.
Also joining The Fantasticks will be current A Little Night Music actor Matt Dengler, who will take over for Leisy as the Mute.
The current cast features Juliette Trafton (Phantom of the Opera) as Luisa, Bill Bateman, Charles West, MacIntyre Dixon, Edward Watts, Tom Flagg, Gene Jones, Anne Markt and Michael Nostrand.
The Fantasticks has choreography by Janet Watson with musical direction by Robert Felstein.
The Fantasticks resumed performances Off-Broadway at the Snapple Theater Center's Jerry Orbach Theater June 16, 2008. The musical began a winter hiatus Feb. 24, 2008, following 27 previews and 628 regular performances at the Orbach Theater. The musical originally opened at the Sullivan Street Playhouse in May 1960 and closed Jan. 13, 2002.
Harvey Schmidt wrote the music and Tom Jones penned the book and lyrics. Word Baker directed the original Off-Broadway company.
Tickets can be purchased by visiting Ticketmaster.com or by calling (212) 307-4100. The Snapple Theater Center is located at 210 West 50th Street at Broadway.