The family later moved to the San Fernando Valley, and again to Guadalupe, where Aratani attended school while his father established several highly successful farming, manufacturing and international trade companies.
Unable to finish his degree at Keio, he enrolled at Stanford University, but after Setsuo's death in April, Aratani, then 22, dropped out to help his stepmother run the Guadalupe Produce Company.
[1][4] In the wake of the attack on Pearl Harbor, and the tide of anti-Japanese sentiment that followed it, Aratani transferred the company's assets from its Issei leaders to its Nisei executives, hoping to avoid losing the business.
The move only postponed what would soon prove to be inevitable; after learning he and his stepmother would be "evacuated" with 120,000 other Japanese Americans, Aratani was forced to leave the Guadalupe Produce Company in the hands of trustees from a separate business.
[4][6] Under his guidance and through his contributions, Aratani helped with the restoration of numerous historical buildings in Los Angeles' Little Tokyo and was key to the creation of its Japanese American Cultural and Community Center.
[4] In 2004, at UCLA, he and Sakaye endowed the United States' first academic chair to study the World War II incarceration of Japanese Americans and their efforts to gain redress.