The real-world child in The Lego Movie is Finn. He is the boy whose imagination creates the film’s animated LEGO world, while the story follows his minifigure counterpart, Emmet.
Finn is shown playing with his father’s LEGO collection in the live-action framing scenes. His father, known in the LEGO world as President Business, objects to Finn rearranging the carefully constructed models and insists that the instructions be followed. This conflict becomes the foundation for the film’s themes of creativity, control, and independent thinking.
A common mix-up is confusing Finn with Emmet. Emmet is the central LEGO character inside the imagined world, but Finn is the real-world child controlling or imagining that world. The name also connects The Lego Movie to its sequel, where Finn’s younger sister Bianca plays with the LEGO characters and changes the imagined setting.