 He was called to the Bar of New Brunswick in the same year, and began practising with the firm of Porter, Ritchie & Riley.In 1955, McKelvey founded the firm of McKelvey Macaulay Machum.That firm later merged with several other firms in the Atlantic provinces in 1990 to become Stewart McKelvey Stirling Scales, now known simply as Stewart McKelvey, the largest regional firm in Atlantic Canada.