Thomas Haythe, who guided New York’s Haythe & Curley in its recent groundbreaking merger with a major Canadian law firm, has resigned from the combined firm amid allegations that he committed sexual harassment at a party celebrating the merger.

The departure of Mr. Haythe, who had been presiding partner of the newly formed 300-lawyer firm Tory Haythe, took place last week following incidents on Nov. 19 in Toronto, according to Les Viner, Tory Haythe’s managing partner.