The Harry Potter star, a well-known supporter of eco-friendly fashion, will chair Kering's sustainability committee after shareholders backed the move.
Kering has faced criticism over its sustainability record.
Former Credit Suisse boss Tidjane Thiam and the head of Chinese ride hailing giant Didi Chuxing, Jean Liu, were also made board members.
Ms Watson, who rose to fame playing Hermione Granger in the Harry Potter films, is known for wearing sustainable clothes from top-tier designers for red carpet events and other public appearances.
