Question: what happened to justin in parks and rec

title: Galentine's Day
text: `` Galentine 's Day '' was written by series co-creator Michael Schur and directed by Ken Kwapis . The episode featured a guest appearance by John Larroquette as Frank Beckerson , the long - lost love of Leslie 's mother , Marlene Knope . When Parks and Recreation co-creator Greg Daniels announced the casting in January 2010 , he described Larroquette 's character as `` He 's the one who got away . '' `` Galentine 's Day '' also included an appearance by Pamela Reed , who has played Marlene Knope in several episodes , and the last of a string of slated guest appearances by Justin Theroux as Justin Anderson , a love interest for Leslie . The episode marked the return of Andy 's band , `` Mouse Rat '' , which was previously featured in the first season finale `` Rock Show '' . His bandmates are played by Mark Rivers ( drums ) , Andrew Burlinson ( guitar ) and Alan Yang ( bass ) , the latter of whom serves as a screenwriter for Parks and Recreation .