Hanna Gullstén and Jari Inkinen graduated from the interior architecture department of University of Art and Design Helsinki 1995 and 1991. Jari continued his studies and had his architect Master thesis approved in spring 2007 by the architecture department of Tampere University of Technology. Collaboration during their studies led Hanna and Jari to establish a design & architecture office and a family. Hanna and Jari's family included three daughters: Hilla (1995), Viola (1998) and Louna (2000).

Hanna Gullstén (born 1965) has been working on versatile design projects in Finland and abroad. In the beginning of her career, Hanna decorated cruise ships, restaurants and department stores. From 1997, Hanna has been working together with Jari at GI. Hanna has been working on distinguished projects such as EU chairmanship conference spaces and Radisson Blu hotels both in Espoo and Tampere; alongside she is enthusiastically working with numerous private home projects.

Jari Inkinen (born 1965) has worked as the managing director of GI since 1988. Alongside design work, he has been teaching in the University of Art and Design Helsinki and in architecture department of Tampere University of Technology. In addition, Jari has actively involved in the development and integration of design & business, business management. Jari was also the operating chairman of board of Interior architects SIO 1998-2000 and 2006-2010 Ornamo foundation's chairman. Jari has lectured in several seminars in Finland and abroad including Scandinavian Universities real estate seminar in Bergen, DEGW Forum in Glasgow and Senate Properties workplace seminar in University of Helsinki.