Stout joins the firm from the payment tech company First Data, where he was global head of strategy and spearheaded the company's initial public offering.
Before that, Stout worked for JPMorgan and worked on the IPOs of Visa, Cielo, and Green Dot.
He also advised on Visa's acquisition of Cybersource and Vantiv's acquisition of Litle & Co, among other mergers-and-acquisitions transactions.
Stout will join the San Francisco-based firm in its New York office.
FT Partners focuses exclusively on the fintech industry. It advised on Heartland Payment's $4.5 billion sale to Global Payments, Vantiv's $1.7 billion acquisition of Mercury Payment, and TransFirst's $1.5 billion sale to Vista Equity Partners.
The media startup The Information ranked firm's founder, Steve McLaughlin, among Silicon Valley's favorite bankers earlier this year. FT Partners has been named Investment Bank of the Year and Investment Banking (or Boutique) Firm of the year by The M&A Advisor.