Fox stepped down from his previous position at the end of May 2020 after a decade at the helm.
He now joins the main board of Barhale as a non-executive director.
Barhale chairman Dennis Curran said: “Steve’s track record speaks for itself but at its heart lies a commitment to promoting strong ethical values and collaborative behaviours,.
“By identifying and encouraging talent from within he has been able to foster a reputation for innovation and new solutions – not least in developing an end-to-end direct delivery model. That approach aligns closely with our own and we welcome the additional thinking he will undoubtedly bring.
“He is a champion of training and development programmes and, like us at Barhale, was early to advocate the importance of wellbeing and occupational health alongside robust health and safety measures. He will be a great fit with the Barhale team.”
Fox said: “Barhale is a business with many of the qualities I admire.
“The longstanding commitment to direct employment and self-delivery together with encouraging and supporting individual development has created a very special sense of common purpose and personal responsibility.
“They have clearly provided the strong foundations on which the business is based. I am looking forward very much to working with the team.”
Fox was replaced at BAM Nuttall by Adrian Savory.
His former role as managing director of infrastructure is understood to be filled shortly by Ian Parish.