Carolan, who left the UK’s largest outdoor media group last year, has been tasked with developing and managing key strategic relationships at Widespace while expanding the UK sales team to help grow its market share.
He will report to Patrik Fagerlund, the chief executive and co-founder of Widespace.
Carolan said: "Once I learnt about the Widespace philosophy of accountability, brand performance metrics and incredible audience reach, taking on this new role was a very easy decision to make."
"Not only are they quickly becoming a leading voice in mobile brand advertising, they’re doing it by promoting a fantastic working environment too."
Following his surprise exit from JCDecaux in May 2014, Carolan has been working as an advisor to the board at 65twenty, the publisher of TheLADBible, and as a commercial strategy consultant at Clear Channel.
Carolan joined JCDecaux 2011 and his tenure has been notable for the growth in the company’s transport division. JCDecaux was also awarded the Campaign Media Awards Out of Home Sales Team of the Year in 2013.
Before JCDecaux he was the advertising director for Absolute Radio for a year. His career in ad sales began in radio, with roles at Capital, TalkSport, BBC Worldwide and Classic FM over a ten-year period. From 2004 to 2008 he was the deputy sales director at Virgin Radio.
Fagerlund said: "We are very excited to have Paul on-board to lead our ambitious UK plans. His reputation and commitment to delivering brand performance for clients made him the perfect fit for the role."