Russell, a Wilderness Explorer stowaway on Carl’s flying house. On their journey, Russell makes several comments to Carl that suggest that Russell’s father and mother are no longer together. Russell’s design was based on Pixar animator Peter Sohn.Docter auditioned 400 boys in a nationwide casting call for the part. Nagai, who is Japanese-American, showed up to an audition with his brother, who was actually the one auditioning. Docter realized Nagai behaved and spoke non-stop like Russell and chose him for the part.
Nagai was 8 years old when cast. Docter encouraged Nagai to act physically as well as vocally when recording the role, lifting him upside down and tickling him for the scene where Russell encounters Kevin. Asian Americans have positively noted Pixar’s first casting of an Asian lead character, in contrast to the common practice of casting non-Asians in Asian parts.