Lars Fahlsten studied at Konstfack University of Arts, Crafts and Design and at the Royal Institute of Technology in Stockholm during the 1960s.
In 1973 Fahlsten designed the chair Sophia together with the designer Lars Norinder for the Swedish company Åry Stålmöbler. The stackable Sophia chair was made of a chromed steel-pipe frame with seat and back made of ABS-plastic but could also be made with upholstery and writing plate. Sophia was a part of a furniture collection specially designed for Kulturhuset, the new modernistic House of Culture in Stockholm, designed by Peter Celsing and inaugurated in 1974.
Fahlsten and Norinder were co-workers at the Celsing architect studio at the time. Sophia was launched at the Scandinavian Furniture Fair in Copenhagen and in 1977 it was part of an exhibition with Swedish Design in China made by Svensk Form. The exhibition Swedish Interior Design was the first international one after the Chinees Cultural Revolution.
