He will succeed Julie-Ann Haines, who will stay in the post until 20 November and starts a new role in the summer of next year.
Mansfield has been with Principality Building Society for around eight years, initially joining as chief operating officer and then taking on the role of CFO in 2022.
Prior to that, he was at Nemo Personal Finance for around 11 years, most recently as managing director.
Before that, he was finance director at 118118 Money for around a year and has also held roles at Sav Credit, Pensions Bank, Barclays and Credit Suisse.
Simon Moore, chair of Principality Building Society, said: “The board is delighted to appoint Iain as Principality’s next CEO. His drive and depth of experience is exactly what the society needs to lead Principality into its next chapter with purpose, pace and clarity.
“I have no doubt that under his leadership, we will build on our strengths and create long-term value for our members and the communities we so proudly serve.”
Mansfield added: “It is an honour and privilege to take the helm of Wales’ largest building society. I am committed to the stewardship of a society that meets the ever-evolving needs of our members of today, and those of tomorrow.”
