Even before she took over as the new chief lawyer for a branch of Marsh McLennan, Katherine Brennan was speaking up about environmental, social and governance issues while driving meaningful change as a corporate counsel at the firm. 

Brennan stepped up to the general counsel role at insurance brokerage Marsh LLC on Tuesday, after having previously served as deputy general counsel, corporate secretary and chief compliance officer for parent company Marsh McClennan, a New York-based professional services firm.