Soji has gained global attention for his role as Mozasu in Apple TV+'s Pachinko based on Min Jin Lee's worldwide best-selling novel.

Soji Arai was born in Niigata, Japan. He is the son of second generation Korean-Japanese (Zainichi) parents. After graduating from Waseda University, he made a major impact on the Tokyo theater world with his starring role of Max in Bent directed by Robert Allan Ackerman. Soji also starred in many other plays including the multi-theater-awarded production of Angels in America, Desire Under the Elms, Three Sisters, Blood Wedding, Balm in Gilead and the world premieres of Strangers on a Train and Tennessee Williams's The Roman Spring of Mrs. Stone. In 2009 he was introduced to worldwide audiences as Toshi, Brittany Murphy's love interest in The Ramen Girl.

Soji's incredible talent has allowed him to work alongside some of the biggest names in the industry, including Oscar winner Rachel Weisz in Amazon Prime Video's Dead Ringers, Oscar winner Youn Yuh-jung in Apple TV+'s Pachinko, and Oscar nominated Rinko Kikuchi in HBO Max's Tokyo Vice.