Sir Leigh-Pemberton joined SG Warburg in 1979, working in debt capital markets and equity sales before moving to Credit Suisse in 1994. There, he served as Head of European Equity Capital Markets, Head of European Investment Banking, and UK CEO, overseeing the firm's investment, asset, and private banking businesses. As of 2013, Sir Leigh-Pemberton served as Executive Chairman of UK Financial Investments and Deputy Chairman of UK Government Investments. He was Chairman of RIT Capital Markets until 2025 and has chaired the Council of the Duchy of Lancaster since 2023. He received a knighthood in 2019 for his services to financial services, British industry, and government.