He was actively involved in the legal profession and was one of the founders of Stewart McKelvey, the largest regional law firm in Atlantic Canada.
His last Supreme Court case, in 1990, was taken on a pro bono basis on behalf of a woman who lost the sight in one eye following a cataract surgery.
McKelvey successfully argued that the evidence led at trial was sufficient to prove a legal claim of negligence.
He also represented the Canadian Coast Guard before a Royal Commission inquiring into the grounding of an oil tanker, Arrow, in Chedabucto Bay, Nova Scotia, in 1970.
The grounding resulted in the spill of 108,000 barrels of oil, leading to questions about the way the Coast Guard had responded to the environmental hazard.
For many years, he was also counsel for the owners of the Irving Whale, an oil carrying barge that sank in the Gulf of St. Lawrence in 1970 and posed a potential environmental hazard.
[2] In the early 1960s, McKelvey faced a decision about his career path, when his name was mentioned for a possible appointment to the New Brunswick Court of Queen's Bench.
McKelvey was a strong believer in the value of solid ethics for lawyers, and toured the country to promote the new code.
Just as lubricants keep a machine functioning, lawyers minimize the frictions in society to keep it functioning.”[2] McKelvey served as president of the International Bar Association in 1979-1980, the first Canadian to hold that post.