Final answer:
Walt Disney's business partner and brother who moved to California with him was Roy O. Disney, with whom he founded The Walt Disney Company.
Step-by-step explanation:
When Walt Disney moved out west to California, he brought with him some key people. One of the most important of these was his business partner and brother, Roy O. Disney. Together, they formed the Disney Brothers Studio, which later became The Walt Disney Company. This partnership was crucial as they complemented each other with Walt's creative genius and Roy's business acumen, enabling them to build a successful entertainment empire.
When Walt moved out west to California, he brought with him his brother, Roy Disney, who became his business partner. Together, they co-founded the Disney Brothers Studio, which later became The Walt Disney Company.