Born in Joliette, Quebec, Senator Dalphond holds a law degree from the University of Montreal and a M. Phil. In Philosophy, Politics and Law from Oxford University, U.K. He began his professional career in Ottawa (clerk to the Supreme Court of Canada, then legislative advisor to the Privy Council) before moving to Montreal to join a national firm, where he practised corporate and business law. In 1995, he was appointed a Justice of the Quebec Superior Court. In 2002, he was elevated to the Quebec Court of Appeal. In 2018, he was appointed to the Senate, where he sponsored changes to the Divorce Act, including defining family violence to include animal abuse, enacted in 2019.