Wren left Balfour early last year during a restructuring after 29 years at the company.
He will start at CSCS on May 1 after beating-off competition from more than 50 applicants for the role.
Wren is currently a board member of ConstructionSkills and chair of its Finance Committee.
He has previously been chairman of the Federation of Piling Specialists, president of the National Specialists Contractors Council and also sat on the Strategic Forum for Construction.
Wren said: “I was keen to continue my career in a role that involves the wider construction industry.
“In addition, I am very supportive of an industry that recognises the importance of training and qualifications to improve performance and to attract new recruits.
“On this basis the chief executive role in CSCS is ideal and I very much look forward to the challenges and eventual rewards.”
Wren takes over from current chief executive Brian Adams who is retiring.