Chelah began her acting career in 2002. Horsdal has since appeared in over 75 commercials, multiple films and TV series. She recently[when?] wrapped lead and supporting roles on "Three Weeks, Three Kids" "On Strike For Christmas," "Marley & Me; The Puppy Years." and Lifetime's The Client List, co-starring Jennifer Love Hewitt and Cybil Sheppard, Plus back-to-back lead roles in Lying To Be Perfect and Mrs. Miracle. Additional credits include leads on the feature Burning Mussolini, Nickelodeon's Gym Teacher: The Movie, co-starring Christopher Meloni and Amy Sedaris, Flirting With Forty with Heather Locklear and the FOX TV pilot The Virgin of Akron, Ohio. Supporting leads include AVP2: Requiem for 20th Century Fox and Possession alongside Sarah Michelle Gellar, as well as Elegy with Ben Kingsley and Penélope Cruz and Rise of the Planet of the Apes with John Lithgow and James Franco. Her performances in the short films Dark Room (2006) and "The Hostage" (2010) both earned Leo nominations for Best Performance. Recurring roles include the critically acclaimed Battlestar Galactica, Exes & Ohs, The L Word, Stargate: SG1, Saved, DaVinci's Inquest, Whistler,, Blackstone,, Clue and, most recently, Cartoon Network's Level Up.
Horsdal appeared in a lead role in the American-Canadian revenge thriller film The Tortured.
"The Hostage," for which Chelah was nominated for Best Actress at the 2011 Leos, co-starred and was produced by her close friends Tahmoh Penikett and Aleks Paunovic.
Horsdal studied acting at Lyric School of Acting in Vancouver. She remains in classes whenever her work schedule permits. Teachers, mentors & coaches include Larry Moss, Ivana Chubbuck, John Cassini, Ben Ratner and Gina Chiarelli.