Ms Seymour-Jackson has been a managing director of the workplace division at Aegon since December 2012 and is also a non-executive director at Rentokil Initial.
Prior to this she was the chief executive of RAC Motoring Services between 2010 and 2012.
She has also held various senior marketing and distribution roles from 1989 to 2011 at Norwich Union Insurance, CGU and Aviva UK Life.
Henderson Group chairman, Mr Gillingwater said he is pleased someone of Ms Seymour-Jackson’s experience is joining the board.
“Her background in retail financial services makes her a welcome addition to the board.”