He continued his career in London, during which time he took silk as a Queen's Counsel, until the Prime Minister, John A. Macdonald appointed him a Judge of the Chancery Division of the High Court of Ontario in 1890, at Toronto.
In 1912, he succeeded his elder brother, William, as Chief Justice of the Court of Common Pleas, his final judicial post, retiring in 1930.
Like many of his brothers he had a great love of flowers and floriculture, and was at his happiest whiling away the hours in his extensive gardens on the Meredith's London estate.
His obituary read, Chief Justice Meredith had a certain self-assurance and impatience with intellects less able than his own that sometimes brought him into sharp conflict with judicial colleagues, but he had a profound knowledge of law, and his ability and fairness earned him the respect of the Ontario Bar... (Out of court) his disposition was very kindly and friendly, and he was at all times a gentleman.
In court he required the most rigorous etiquette, but his strict fairness and careful attention to details made him respected by all members of the Bar.
In 1901, he presented a chime of ten bells, cast in England, and the clock on the clocktower to St. Paul's Cathedral (London, Ontario) in memory of his parents.