Baker will start at the fast-growing discount designer-fashion and homewares group in January as UK marketing vice-president.
Baker has been at Ann Summers for three years and oversaw the brand’s repositioning as well as the relaunch of its web site and the Knickerbox brand.
He said he had enjoyed his time at Ann Summers, but that the TK Maxx role was “a great opportunity in a great business”.
Ann Summers chief executive Jacqueline Gold said she will split Baker’s existing role in two, recruiting a marketing director and an e-commerce director “to prepare the business for our next phase of growth”.
TK Maxx, which is owned by US giant TJX, has 210 shops in the UK, Ireland and Germany. Two weeks ago, the retailer opened its first central London shop in Kensington.