Jordan Nagai

From Pixar Wiki

Jordan Nagai (born February 5, 2000) performed the voice of Russell in Up. He was seven years old when he got the part. Originally, his older brother Hunter was auditioning for the part of Russell, but Jordan stood out in the group of 400 children because he wouldn't stop talking. However, he was quite shy and Pete Docter mentioned it was sometimes difficult getting him to say all of his lines.

He currently resides in Los Angeles, California.