The track's lyrics tackle the difficulties of letting go after a breakup. Kiesza explained on a Reddit AMA: "The idea from 'Giant In My Heart' came from my own experience of letting go of a person I wasn't ready to let go of. I think excepting that love is over is very hard, but something we all have to go through, which in the end makes us stronger people."
The song's music video follows a frustrated New York businessman, who is tired of the stresses of his unsatisfying office job. It is revealed that he leads a second life at nighttime in which he dresses up in drag.