In-Ah Mellor was born in Duesseldorf, Germany, and studied animation in high school before earning a two-year higher diploma in 2D character animation from the Lycée Technique des Arts et Métiers in Luxembourg. She went on to complete a 3D animation degree at GOBELINS, followed by a postgraduate year at the Filmakademie Baden-Württemberg.

During her career in VFX and animation, In-Ah has worked on feature films for Framestore (including Harry Potter and the Goblet of Fire), Guerilla Games (facial animation R&D on Killzone 2), Double Negative (Iron Man 2 and Paul), and Sony Pictures Imageworks (Lead Animator on The Smurfs, Hotel Transylvania, and Cloudy with a Chance of Meatballs 2, and Supervising Animator on Oz the Great and Powerful).

After finishing work on The Amazing Spider-Man 2, she joined MPC to work on Guardians of the Galaxy and Goosebumps, later teaching character animation at Vancouver Institute of Media Arts, before founding Deadbird Animation Ltd, where she currently works as an artist and illustrator.