Olofsson attended upper secondary technical school at Pauliskolan in Malmö and graduated as Master of Science in Engineering at Lunds Tekniska Högskola in 1974. After his education, Olofsson began a career in the technology consulting industry. He started at VBB (what is now Sweco) where he during the 1979 oil-crisis became group manager for a new venture in energy technology.

Later, Dan Olofsson proceeded to become region manager for Skandiaconsult’s southern division and, after another year, business controller. After a conflict of interest amongst the owners, Olofsson chose to leave the company and, together with John Wattin and Ronny Forsberg he founded the consulting company Sapia in 1986. Olofsson was assigned the task of building its technical consultancy part, Sapia Teknik. In 1989, he became manager for the entire Sapia group. In 1993 Olofsson acquired Sapia Teknik along with its 400 employees. The company was renamed Sigma, and an IPO took place in 1997.

By 2001, the business had grown to over 3,000 employees and Sigma was divided into three different stock exchange companies in each business area under the names Sigma, Epsilon and Teleca. Olofsson became chairman of the board and principal owner for all. He has since managed the business through his own family-owned holding company Danir AB, where Dan Olofsson’s son Johan Glennmo is the CEO.

After having devoted himself to his great hunting interest in Africa, Olofsson and his wife Christin in the early 2000’s decided to build up the safari facility Thanda Safari with more than 14,000 hectares of land in KwaZulu-Natal in eastern South Africa. The facilities were inaugurated in 2004 by the Zulu king Goodwill Zwelithini KaBhekazulu and between 2009–2016 it has, amongst many awards, been named “The World’s Leading Luxury Lodge” by the World Travel Awards. In 2016, the exclusive marine reserve resort, Thanda Island opened just off the coast of Tanzania and was chosen “The World’s Leading Exclusive Private Island” by World Travel Awards.

Olofsson’s philanthropic commitment is best seen through the organization Star for Life, which he and his wife Christin launched in 2005. So far, 450,000 young people has participated in a three-year preventive programme against HIV/AIDS, promoting a healthy way of life, in South Africa, Namibia, and Sri Lanka. Today, Star for Life is also established in Sweden as the foundation Motivationslyftet, aiming to strengthen young people’s self-esteem and belief in the future.

The Danir group consists of some 90 subsidiaries with more than 7,500 employees in fifteen countries. During a number of years, the group has had a healthy organic growth and in 2019, had a combined sale of SEK 6.4 billion. Sigma, a group of IT and tech consultancy companies, makes up the majority of the Danir group. The consultant brokers A Society, staffing and recruitment company Poolia, and the Thanda companies are also part of Danir.

Aiming to counteract the depopulation in villages in Norrland’s interior, Project Kaxås was launched in 2019. The idea is to invest in young families wanting to live a safe life, close to nature, and yet with access to a well-functioning labour market in Östersund and Åre.