While not one of his early recruits, Dr. Blaustein said his arrival at Maryland coincided with the beginning of a "new era," which he attributed to Dr. Dennis.

"John ushered in many new things that were later built upon by others, and played an enormous role in getting the new Veterans Administration hospital built downtown," he said. "He was an awfully nice guy but could be tough when he had to make difficult decisions."

Another skill that Dr. Dennis possessed, colleagues said, was his ability to bring people together. For many years, he was the leader of Friday afternoon social gatherings that brought medical school faculty and staff together to talk over problems and find common ground and solutions.

During his tenure, the University of Maryland rose to among the top third of medical schools, as measured by research grants. An editorial in The Baltimore Sun at the time of his retirement in 1990 said, "He, more than anyone, is responsible for the construction of a new Veterans Administration hospital on the UMAB campus."

In addition to recruiting top-flight personnel for departmental chairs, Dr. Dennis successfully made the medical school into a major player in the field of bio-medical research, and "managed twice to re-build UM's basic science programs. He took an average medical school and made it better," said the editorial.

Dr. Earl P. Galleher Jr., a retired Baltimore urologist, was a longtime close friend.

"John was such an outstanding and fabulous person. I got to know him when I came up from Duke in 1958 to join the urology department," said Dr. Galleher, who lives in Lutherville. "He and I did a great deal of work together in patient care. He was a man who accomplished a great deal."

Dr. Galleher said he was "extremely kind and well liked by everyone from the residents and staff all the way down to the patients. And he was always very popular with people who had gone to Maryland."

Dr. Dennis had served as president of the American College of Radiology, which awarded him its Gold Medal in 1980. Loyola University Maryland presented him its Andrew White Medal for giving "himself … devotedly to the medical profession."

Dr. Dennis was a longtime active member of the Maryland Club and Baltimore Country Club, where he liked golfing.

"He was also a member of the Monthly Medical Reunion Dinner Club, which was founded in 1881 and is one of the oldest medical dinner clubs in the country," said Dr. Galleher.

For years, Dr. Dennis lived in the Hampton section of Baltimore County, and since 2009 resided at the Blakehurst retirement community in Towson.

In his retirement, Dr. Dennis enjoyed making furniture and became an accomplished watercolorist.

Dr. Dennis was an active communicant of the Roman Catholic Cathedral of Mary Our Queen.

A Mass of Christian burial will be offered at 11 a.m. Monday at Alumni Chapel on the campus of Loyola University Maryland, 4501 N. Charles St.

Surviving are his wife of 65 years, the former Mary Helen France; two sons, the Rev. John M. Dennis of Indianapolis and Patrick F. Dennis of Newnan, Ga.; two daughters, Lori D. Mulligan of the Charlesbrooke neighborhood of Baltimore County and Terry D. Passano of Princeton, N.J.; eight grandchildren; and two great-grandchildren.