Lalonde appears on the television channel SCREAM. She has made guest appearances in Mutant X, Queer as Folk, Kevin Hill, Beautiful People, Battlestar Galactica, Jeff Ltd. and Love Bites. Lalonde has appeared in numerous commercials including Molson's "It Starts Here" ad campaign as Allison the cowgirl on the airplane. She has been seen in commercials for Kit Kat (playing a snobby socialite daughter) as well as in a commercial for Special K cereal (as a devastated girl who just broke up with her boyfriend) and also a Leon's commercial.

Lalonde is represented by B&M Model Management for modeling and Amanda Rosenthal Talent for acting.[citation needed] She was previously a high school teacher at Notre Dame College School in Welland, Ontario and in New Zealand. She now works as a substitute teacher at The Bishop Strachan School ¨Toronto,Ontario.

Lalonde completed her first two feature films in 2006: Heartstopper and 5ive Girls. She then starred in George A. Romero's Diary of the Dead, released in February 2008. Her TV Movie of the Week appearances include Murder in the Hamptons, Earthstorm, Nature of the Beast (ABC Family-Disney), and CBC's Victor: The Victor Davis Story.

In 2008, she will reprise her leading role on CBC's new series Sophie for a second season. The first season will be airing in 2009 on ABC Family in the United States, as it was purchased by ABC in February 2008. While filming the second season of Sophie in Montreal during the summer, Amy also traveled to Calgary to complete season one of a new CBC drama, Wild Roses.