In 1997, Spalding relocated to Vancouver, British Columbia, where she worked as an executive story editor and writer on CBC Television's prime-time drama Da Vinci's Inquest. She also worked as a writer and executive story editor on all three seasons of The Eleventh Hour, a prime-time drama about investigative journalists on CTV. Both series were highly critically acclaimed and repeatedly won Gemini awards for Best Series.
Currently, Spalding is the showrunner on Showtime's On Becoming a God in Central Florida, and a writer and executive producer on Freeform's Party of Five. Her feature film The Last Letter from Your Lover (co-written with Nick Payne) based on the novel by Jojo Moyes will premiere on Netflix in July 2021. She recently published a children's book series that includes Look Out for the Fitzgerald-Trouts, Knock About with the Fitzgerald-Trouts, and Shout Out for the Fitzgerald-Trouts.
Spalding and her mother Linda Spalding co-wrote a novel, Mere, which was published in 2001.
She is a contributing editor to the literary magazine Brick.