He has a wealth of experience within financial services, having previously worked for Leeds Permanent Building Society and the Halifax.
In his new role at the Society, Stewart will be formulating and driving forward the Society's marketing and communication strategies in order to further improve the outstanding customer service feedback of 92% satisfaction.
Commenting on his appointment, Stewart said, "Leeds Building Society is a highly successful and well organised organisation that delivers the products and services its customers want through a variety of channels to suit customer demand.
"I hope to bring new insights to develop and deliver highly competitive mortgage and savings products through our national branch network, our call centre based in Leeds, through the internet and via postal channels."