The film partnered with Claire's Place Foundation, a charity providing emotional and financial support to families struggling with Cystic Fibrosis. The actors and director worked closely to accurately depict cystic fibrosis in the film.
Claire Wineland worked closely with the leads to perfect the roles of cystic fibrosis patients. Claire died of a stroke in September 2018, right after a successful lung transplant.
Much of Will's artwork is penned by Caesar Meadows, a New Orleans based graphic artist known for his local strip, Mumbeaux Gumbo.
The balloons Stella uses for Will's birthday are purple. Purple is the official color of CF patients.
Cole Sprouse filmed this movie during his break between seasons 2 and 3 of The CW show Riverdale (2017).