Seiichi Okauchi graduated from Junior College Department of Kansai University (1921). Began the practice of law (1922).
Became auditor (1930) and then president (1947) of Kochi Mujin Kaisha (Mutual Loan Company) which later was reorganized and renamed Kochi Sogo Ginko. Held various additional posts including those of chairman of Kochi Lawyers' Association and supervisor of Kochi Prefectural Chamber of Commerce & Industry. Served also as director of Kochi Chamber of Commerce & Industry (since 1950).