SOL stems from Lindström Oy, one of the oldest businesses in Finland still in operation. In 1848, the dye master C.A. Lindström founded a dyeing house where the Parliament House of Finland is located today. In 1922, Lindström was purchased by the originator of the current owner family, chief engineer Johan Roiha, who in 1913 founded a white textiles laundry.

In 1991, Liisa Joronen, granddaughter of Johan Roiha, acquired the cleaning and waste services from the family business, gave them a new look and renamed them in early 1992 as SOL Siivouspalvelu Oy, with SOL Jätepalvelu Oy as its parent company. The sunny name was chosen on the basis of the suggestions of the staff. The revenue of SOL was already in 1993 about EUR 30 million and the number of staff was about 2,300.

Liisa Joronen was interested in management and the internal growth of staff and defended her doctoral thesis in 1993 at the University of Helsinki with the subject “Prerequisites for professional growth in organisations”. The research target and field of experiment in her pedagogical and sociological studies was her own company.

Rikaton Oy, incorporated by the city of Helsinki, was purchased for Sol Jätepalvelu Oy in 1996 and they were merged into SOL Ympäristöpalvelut Oy. This company was sold in 1999 to a German operator. In 1999–2001, SOL also operated as a rental service for textiles and carpets. SOL Tekstiilipalvelut Oy was sold to Lindström. Since 2001, the consumer laundry services remaining with Lindström have been a part of the SOL Group and operate as SOL Pesulapalvelut Oy.

SOL has provided property services since the 1990s and considerably developed them and their facility services in the 2000s. In the late 2000s, SOL has also expanded its security services to, for instance, guarding and security check services. At the end of the decade, SOL was among the five largest security service providers in Finland. In 2009, SOL expanded into personnel services by purchasing a limited company, offering temp and recruiting services, known today as SOL Personnel services Oy.

After the diversification of its operations, the name of the company providing cleaning, facility and property services was changed into SOL Palvelut Oy, with SOLEMO Oy operating as its parent company since the beginning of 2008. The international operations of SOL were launched in Estonia in 2001 and have expanded to Latvia, Lithuania, Russia and Sweden, each with their own affiliate.

Since the beginning, Liisa Joronen has acted as the Chairman of the Board of Directors of SOL, and until 2011, Anu Eronen acted as the Managing Director. Since September 2011, Peppi Kaira has served as the Managing Director of the group parent company SOLEMO Oy and Juhapekka Joronen as the Managing Director of SOL Palvelut Oy.