He started in the Investment Banking Division (IBD) and served on the Firmwide Commitments Committee and the IBD Americas Operating Committee. He was head of the Americas ECM Group and the Asia ex Japan ECM Group. He previously held various leadership positions in the Financing Group, both in Hong Kong and New York. John is also a co-founder of 25madison — a venture studio focused on incubating early-stage start-ups and venture capital investing.

John is a member of Trinity College Dublin's Provost’s Council and the Advisory Board of Trinity College Business School. In addition to serving as a Board member for The Michael J. Fox Foundation, John also serves on the Board of Directors of the Irish Arts Centre in New York. John graduated with a BAI in Engineering and a BA in Mathematics from Trinity College Dublin. He also earned his MBA from the Wharton School of the University of Pennsylvania.