Parrish was born on Oahu, Hawaii, to Mark Parrish, who is of European-American descent, and Joanne, who is of Han Chinese ancestry.

Parrish first achieved fame in Hawaii as the winner of local talent contests. She got her start as a professional entertainer when she was cast as "Young Cosette" in the National Touring Company of Les Mis??rables , and later portrayed "Young Cosette" in the Broadway production as well; the role showcased both her acting and singing abilities. She subsequently appeared in several community theater productions in Hawaii???most notably as "Scout" in Manoa Valley Theatre's revival of "To Kill A Mocking Bird" in 1998.

She got her first off-stage acting job as a minor role in 1999's four-part miniseries . Shortly after, she appeared in two episodes of Baywatch as a young girl named Hina. In 2000 she was featured in Disney's made-for-TV live-action incarnation of the Pinocchio story entitled Geppetto . She then went on to appear as the character Vanessa in the short-lived sitcom The O'Keefes, as well as appearing in many Disney shows and made-for-TV movies on the Disney channel. Along with appearances on The Bernie Mac Show, Zoey 101 (where her costarred with her future fellow Pretty Little Liars costar Tammin Sursok), and The O.C. One of her recent acting roles has been the theatrical Bratz motion picture, as one of the main characters, Jade . It is her first role in a theatrical motion picture as well as her first starring role. She has also landed a recurring role in the hit NBC series Heroes .

Janel began playing piano at age six. At age 14, on January 3, 2003, she appeared on the 2003 remake of Star Search, performing the song "On My Own". The judges were Naomi Judd, Ben Stein, Carol Leifer, and Jack Osbourne. Stein commented that she had a "lot of talent, but not quite up to the top rank", giving her four stars, along with Osbourne who simply called her performance "good" and also gave her four stars. Leifer remarked that she had a "great Broadway voice" giving her three stars. Finally, Judd was the least generous, stating "You have a future in musicals, but you have some work to do. You've got some practicing to do" and giving her two stars. Janel was eliminated after this performance in favor of competitor Tiffany Evans who received a perfect five stars from all four judges.

In 2007, she was signed to Geffen Records to produce her first album. Her first single, "Rainy Day", one that she has written, along with its music video, was released on July 7, 2007, and was also featured on the Bratz Motion Picture Soundtrack . She also makes a brief appearance in Prima J's "Rockstar" music video, which is also on the soundtrack. She also made an appearance in NLT 's "She Said, I Said" music video. She provided backround vocals for the song.

Parrish was cast as Mona Vanderwaal in the TV series Pretty Little Liars based on the book series by Sara Shepard.

Year	Film	Role	Notes
1999	''Too Rich: The Secret Life of Doris Duke''	unknown	uncredited
	''Baywatch''	Hina	2 episodes
2000	Geppetto''	Featured
2003	''The O'Keefes''	Vanessa	1 episode
2004	''The Bernie Mac Show''	Laura	1 episode
2006	''Zoey 101''	Sara	1 episode
	''The O.C.''	Leah	1 episode
2007	''Bratz: The Movie''	Jade
	''TRL''	Herself	Guest
	''Discovering Bratz: Auditions And Casting''	Herself
	''Bratz: The Movie''	Jade	VG
	Heroes''	May	3 episodes, 2007???2008
2009	Fired Up!''	Lana
	''Triple Dog''	Cecily
	''April Showers''	Vicky
	''True Jackson VP''	Kyla	1 Episode
2010	''One Kind Day''	Leilani
	''Knots''	Hoku
2010 - present	''Pretty Little Liars''	Mona Vanderwall	Supporting character

Year	Film	Song	Notes
2007	''Bratz''	''Rainy Day''	Writer/Performer
2008	''Guiding Light''	''Won't Let You Go''	Writer; Uncredited
	''Guiding Light''	''Won't Let You Go''	Performer; Uncredited
2009	''April Showers''	''I Won't Cry''	Performer
	''The Kings Of Appletown''	''I'm Changing''	Performer