breakingbadfunfacts: 4. Did You Know? RJ Mitte auditioned for the role of Jesse and got the part. The reason he ended up as Walt Jr. was because Bryan Cranston owed a favor to Aaron Paul, and to make it up to him, he brought Aaron to meet Vince Gilligan. Vince was so impressed by Aaron’s verbal skills that he knew he was perfect for the role of Jesse. RJ was then cast as Walt Jr.