His stamina was legendary. He treated around 500 patients a year, wrote or co-authored 13 books, contributed scientific papers to standard texts, lectured and taught younger surgeons in the United States, Australia and elsewhere, and made himself readily available for consultation.

Fazio was attending a conference in Paris in 1981 when doctors consulted him from Rome. They had operated on a man suffering serious gunshot wounds but were uncertain about the outcome. Several long-distance consultations followed with Fazio and two other American surgeons and Pope John Paul II survived.

Friends in the United States said that Fazio would have succeeded in any profession he chose, that he would have been "at least a cardinal in the Catholic church". In Australia, an irreverent friend called him "the Pope's bowel doctor".

Victor Warren Fazio was born in Sydney on February 2, 1940, and spent most of his childhood in Tuncurry and Taree. His father, also Victor Warren, was the son of Vincenzo Fazio, an Italian fisherman from the island of Lipari, who settled in Tuncurry in 1896. Victor snr won a Distinguished Service Medal in the navy during World War II and had five sons, including Victor jnr and Joseph from his second marriage, to Katherine Hills, who wrote poetry, encouraged her son to pursue medical excellence and whose convict forebears, James Triffitt and Mary Higgins, had settled in Tasmania.

Victor jnr attended St Joseph's College, Sydney, and began medical studies in 1957, hoping to become a GP in Taree and living in Randwick at a Legacy hostel for the student sons of men who had died during the war or as a result of war.

Like many medical students, Fazio failed two years. Legacy leaders, with limited resources, questioned their support but Fred North, from Taree, had seen promise in the lad and fought for him.

Fazio graduated in 1964, by which time he had played junior rugby league in the Eastern Suburbs competition and rugby for Sydney University, married Carolyn Sawyer in Taree, become a father and driven taxis at night to support his young family. He completed postgraduate work at St Vincent's Hospital, lectured in anatomy at the University of NSW and served with the Australian surgical team at Bien Hoa during the Vietnam War.

He went to the United States to hone his skills in all aspects of intestinal surgery, firstly at the Lahey Clinic Medical Centre in Boston, then, in 1973, to learn alongside surgeon Dr Rupert Turnbull at the Cleveland Clinic. Within a year, at the age of 35, he was chairman of the clinic's department of colorectal surgery, one of the youngest doctors to hold such a post in the United States; he held it for 33 years. In 2008, he became chairman of the clinic's digestive disease institute.

Dr James Church, a colleague, said: "He is responsible for the evolution of the best colorectal unit in the world … His knowledge is astronomical, his clinical acumen sharp and well honed, his surgical skills are without peer … he was bold when boldness was called for and cautious when caution was needed. His outcomes stand as testimony to his skill and his patients' fondness for their surgeon is what we all hope to engender."

Church thought Fazio's personality "magnetic and charming in a rough Australian 'G'day mate' type of way." Patients liked Vic's sense of humour. On his death from leukaemia at 75, Norma Carpenter, of Warren, Ohio, wrote her condolence. A patient for 30 years, she had thanked him after one operation lasting 10 hours. "Thank you," Fazio chuckled, "for my new BMW."

Specialising in colon and rectal surgery, his clinical interest were Crohn's disease and ulcerative colitis, colorectal cancer, and pelvic floor reservoir procedures, created inside the body of patients who had intestines removed, to collect the body's waste. His innovative techniques allow patients to avoid the need for colostomies. He also made an international mark by developing techniques to conserve small intestine in patients with extensive Crohn's disease.

The University of Sydney made Fazio an honorary Master of Surgery and he became an officer in the Order of Australia in 2004. He was particularly grateful to be honoured for contributing to the education of young Australians and surgeons of other nationalities. The multiplying number of well-trained colorectal surgeons around the world are among his legacies.

Fazio's honours and awards were extensive. He is one of only three Australians to receive a Fellowship of the Royal Australasian College of Surgeons both by examination and by conferment of an honorary degree. His honorary fellowships and doctorates come from England, Edinburgh, Ireland and Poland and he was inducted into the European Surgical Association in 2007.

Frequently named among America's top doctors, he was the first recipient, in 2000, of the Cleveland Clinic's Master Clinician Award, given to one of 1500 Cleveland Clinic physicians. He was inducted into Cleveland's Medical Hall of Fame in 2002.

In the same year he was the first winner of the Al and Norma Lerner Humanitarian Award, the clinic's highest honour. It goes to a doctor who personifies "the highest values of the medical profession, a practitioner of peerless expertise, wise mentor and valued participant in the life of the institution". Fazio was judged to be a "physician whose selfless dedication, boundless compassion and tireless work has made the most profound and singular contribution to the good of humankind."

He earned The Cleveland Clinic Alumni Association's 2005 Distinguished Alumnus Award and was the clinic's Teacher of the Year twice. The Crohn's & Colitis Foundation made him the Premier Physician. Good Housekeeping magazine named him one of the country's top cancer doctors for women; American Health said he was one of the best doctors in America. The Goodreads website recommended his Atlas of Intestinal Stomas.

Last year Fazio won the Lifetime Achievement honour in the National Physician of the Year awards. Despite failing health, he was working on a new edition of one of his books and principal investigator in an international multicentre clinical trial of pelvic reservoirs. Plans are proceeding to establish the Victor Fazio Centre for Irritable Bowel Disease at Cleveland, and surgical suites in his name for digestive disease patients.

He never lost his Australian accent, although it took on traces of the American over the years. Back home, Carolyn and Vic have been patrons of the historical society at Tinonee, near Taree, and supporters of the Great Lakes Historical Society at Tuncurry.

Victor Fazio is survived by Carolyn – he often said, "Carolyn is smarter than I am" – sons Victor and David in the United States, daughter Jane, in Adelaide, their families, including six grandchildren, stepbrother Vince and stepsister Noeline. Vic's younger brother, Joe, predeceased him, having survived a shell explosion at Singleton army camp that killed a mate in 1959 to win a silver medal in Australia's rowing eight at the Mexico Olympics in 1968.

A mass of Christian burial was held in Shaker Heights, Ohio. Vic Fazio will be buried at Tinonee on July 25.