Larsson was renowned for his use of photojournalism to record and document the cultures of the south Mediterranean, primarily within the Palestinian region. Larsson was also a well respected diplomat of Sweden who acted as the vice consul and consul to Jerusalem and in that role acted in the best interests of the American Colony. Lewis Larsson was the only son of Hol Lars Larsson and Israels Brita Ersdotter born in Nås, Sweden.
His father died when he was only three years old and he was raised by his mother.
In 1896, many of the residents of Nås emigrated, following the evangelist Olof Henrik Larsson, to the American Colony. This included Lewis and his family, and in 1896 they traveled mostly by train to Jerusalem in order to wait the "Return of the Lord" Lewis married Edith Larson, the daughter of the evangelist Olaf Larson.
In 1904, Larsson succeeded him as head of the department, which was becoming quite profitable. Larsson took the position of Swedish Consul General to Jerusalem in 1921, succeeding Gustav Herman Dalman who served in that position from 1911 to 1914.
The new position caused him to cut back on his photography work with the American Colony.