In 1922 Yoshiyuki Okajima graduated from Tokyo Commercial University.
Immediately entered Nihon Menka (Japan Cotton Company) and served with its New York, Texas and China branch offices. In 1945 he became director and senior managing director. Served also as permanent director of Nihon Boekikai (Japan Foreign Trade Association) and member of Tsusho Shingikai (Trade & Commerce Council).
He was president of Nichimen Jitsugyo in Japan Cotton Company (since 1951) and chief director of Nihon Menka Kyokai (Japan Cotton Association).