In 1954, Jiro Matsumura established Homat Homes Ltd. to provide comfortable and fully equipped residential houses for expatriates from many foreign countries. Such houses were in short supply in war devastated Tokyo. He was a visionary who embraced the challenge of blending East and West in building houses for expatriates in post war Tokyo expecting contemporary facilities and also wishing for the charm of traditional Japanese accents. He delivered both. These houses were welcomed by them, and had a good reputation. In 1963, he started to build residential apartment complexes for foreign executives, totaling more than 100 completed buildings, with a good reputation, and the brand name of "Homat" apartments.

Jiro Matsumura's philosophy in building residential apartments for expatriates was to provide living space where they could enjoy comfortable living in Japan according to international standards and fully equipped with the appliances they would expect to have in their home country. On the other hand, he wanted to combine the traditional styles of beauty in Japanese culture in the houses he built, and skillfully carried out his desire to combine the two cultures, in both inside and outside elements. This was exemplified in Homat buildings outside by the use of the flagstone (Teppei-seki) for fences and walkways, Japanese stone lanterns, and small fish ponds. Inside, by paper screens and sliding　doors. He also attached great importance to planting trees and shrubbery in abundance around the exterior, so that the building would be in harmony with nature. He created roof top gardens with greenery, so residents of apartments could enjoy outdoor living, which was quite an outstanding idea at the time. Not many people paid attention to the greenery surrounding their apartment building. The Homat apartments that he created fit nicely into residential areas of central Tokyo as hallmark buildings.

There are many ex-Homat residents who happily remember the experience of having lived in Homat apartments during their stay in Japan. Jiro Matsumura, as a civilian diplomat and through his distinctive buildings, made an outstanding contribution in introducing Japanese culture to the international community.

Besides his achievements in unique buildings, he served as Vice-Chairman of the Tokyo American Club for many years. His portrait has been placed in the Hall of Presidents as a Permanent Honorary Chairman of the Club. He was also a member of the Japan-American Society, the Japan-British society, and the Foreign Correspondents Club of Japan, and was quite active in international exchange programs, extending invitations to Chinese scholars to study in Japan with tuition assistance.