In her new role, Konarzewski (pictured) is responsible for global communications and branding, including all external and internal comms, and corporate affairs. She also becomes chief communications officer of WorldQuant, Millennium's affiliated global quantitative investment firm.
Konarzewski replaces Tripp Kyle, who moved to Citadel to become chief corporate affairs and communications officer in April.
New York-headquartered Millennium, which was founded in 1989, currently manages assets worth $46.3bn and employs more than 3,200 people. Konarzewski's role is split between New York and London.
Konarzewski joined Man Group in January 2014 as global head of communications and marketing. In that role she oversaw comms, marketing and branding. This included work on Man Booker while the firm sponsored the famous literary prize.
Prior to Man Group, Konarzewski was one of the founding partners of financial PR agency Greenbrook. Before that, she led comms for The Carlyle Group across Europe, the Middle East and Africa.