McNicholas is Group Managing Director Utilities at Kier who bought his family firm McNicholas Construction for £24m in 2017.
He has decided to leave Kier at the end of Decemberto to pursue non-executive opportunities.
Andrew Davies, Kier Group CEO said: “I would like to thank Barry for his hard work over the past few years.
“Since Kier acquired McNicholas in 2017, Barry has been an integral part of our leadership team, and I wish him every success in the future.
“I am pleased to announce that Andrew Bradshaw, currently Commercial Director, Kier Highways, has been promoted to the role of Managing Director Utilities with effect from 1st December 2021”.