Hiroshi has been a distinguished practicing attorney in the area of business. He started his career as a practicing attorney in 1986 at Law Firm of Matsuo & Kosugi, a general practice law firm in Japan. At Matsuo & Kosugi, he practiced business laws such as Company Act and worked on broad cases such as international joint venture agreements, international license agreements, and litigation in the area of intellectual property and product-liability. He has been appointed as a court-appointed administrator and as a court-appointed supervisor in the area of bankruptcy, civil rehabilitation and corporate reorganization. From 1995 to 1996, he was a professor at the University of Leuven in Belgium. In 2004, he founded Uchida & Samejima Law Firm with Masahiro.
He passed the Bar Examination in Japan and graduated from Kyoto University in 1984 (Bachelor of Laws). As his community activities, he has trained legal apprentices and law school students.