Kath Brown, who was Marie's deputy on Elle at Emap, becomes associate editor on Marie Claire. Brown was launch editor of Attic Futura's teen title Sugar and Emap's Red.
Stuart Selner was creative director at Arena and takes up the same post on Marie Claire. He was creative director for the launch of FHM in the US.
O'Riordan said, "This is a seriously heavyweight team and reflects the company's commitment to the brand and its ongoing development within this hugely competitive sector."
Marie Claire is published by European Magazines, a joint venture between IPC Media and Groupe Marie Claire.