Forseke succeeds Lesley Knox who said last year she intended to step down from the role. She will join the board of the company on 1 March to allow for a one-month handover period.
Her current role on the FSA straddles deputy chairman and senior independent director and she also holds a non-executive directorship at Wallenius Lines AB.
Previously Forseke was chief executive officer of D Carnegie & Co and before that chief operating officer of the London International Financial Futures and Options Exchange.
Knox, said: "I am delighted to welcome Forseke as the next chairman of Alliance Trust. She has extensive experience of financial services and this, alongside her international perspective will be invaluable."