He takes up the new role in October and also joins the senior leadership team.
Willcock joins after leading Alstom’s systems, signalling and infrastructure business for seven years.
He has also held senior roles at train operating company Go-Ahead Group, and Vinci, where he helped to develop its nuclear power station construction business.
Skanska UK President and CEO Gregor Craig said: “Jonathan has a proven track record of leading successful businesses.
“His senior leadership experience in the construction industry will add greatly to Skanska’s infrastructure expertise.”
Willcock said: “One of the things that really attracted to me to Skanska is its values and its commitment to responsible business.
“I’m excited about joining the company and realising the huge potential in the infrastructure market.”