He replaces Anthony Morgan in the role who is remaining at the firm as an executive director.
At Balfour Tomkins led on operational safety, construction and quality overseeing a wide range of infrastructure and construction projects in the North and Midlands division.
He will be rejoining Griffiths having worked for the firm in 2013/14 when it was known as Alun Griffiths contractors.
During that time Tomkins worked on the Circuit of Wales project and was due to lead the construction programme before the scheme was shelved.
Griffiths became part of Tarmac’s Contracting business in 2017.
Paul Fleetham, managing director, Tarmac Contracting, said: “We are very pleased to welcome Stephen to Griffiths.
“His leadership skills, experience and passion for the civil engineering sector will be a huge asset as we continue to move the business forward.”