Lord Barwell was previously Number 10 Downing Street’s Chief of Staff, and will now work to provide insight on geopolitical and macroeconomic trends.
He will also provide advice on “large scale organisational and transformational change” across the UK.
His appointment was approved by advisory committee ACOBA, and took effect from 1 January 2020.
Kevin Ellis, PwC UK Chairman and Senior Partner, said: “Lord Barwell has a wealth of experience and we look forward to working with him.
“The UK is embarking on a new chapter as it seeks to forge new trading relationships while, at the same time, responding to significant technological and geopolitical challenges.”
He added: “In a post-Brexit world it will be more important than ever to provide deeper insight to our clients as they work through their challenges and opportunities so they can achieve their growth ambitions and long-term sustainability.”