New Brunswick business tycoon John E. (Jack) Irving died Wednesday in Saint John at the age of 78 following a brief illness.

The loss was felt throughout town as Irving-owned businesses lowered their flags to half-staff.

"Jack was a very private person. He was shy, tremendously thoughtful of others and was a delight to work with," said Pat Darrah, executive director of the Saint John Construction Association.

Irving, the youngest son of Irving Oil founder K.C. Irving, headed a number of construction and engineering companies for the family business and was involved in property management.

His family released a statement, describing the man as a "great brother and friend."

"Today is a very sad day for me as we mourn the passing of my brother Jack," James K. Irving said in an email to The Canadian Press. "Jack was a great brother and friend. We enjoyed many happy years growing up together -- at home and in the business. He will be greatly missed."

Irving joined the family business in 1952 at his father's request to work at Irving Oil.

Jack Irving was the youngest of the three Irving brothers, James K. and Arthur Irving, who each shared the ownership of the worldwide family empire.

"For more than 50 years, Jack Irving was truly the builder of the family," New Brunswick Premier Shawn Graham said in a statement. "He was responsible for the design and construction of the facilities that have made the Irving Group the presence it is in our region, from service stations and stores to oil terminals and countless other facilities."

Jack Irving managed construction and engineering projects, including retail outlets, plants and other major infrastructure.

Former publisher Jonathan Frankin, who was at one point hired by Irving to publish newspapers in Moncton and Saint John, told CTV Atlantic that the thriving businessman had a genuine interest in construction.

"The thing I liked so much about Jack is that he just came alive with machinery -- big machinery and big buildings," he said, while recounting the time when he and Irving spent hours at night speaking with workers to get a sense of how things operated at a work site.

Irving's success was recognized throughout Canada. He became a member of the Order of Canada in 2008 and although he was the least well-known of the Irving brothers, earned many accolades for his business dealings. He earned several honourary degrees and was inducted into the Canadian Business Hall of Fame.

Irving also had a reputation as a philanthropist who supported education, the arts and the restoration of heritage properties.

"He has left behind a shining legacy of business leadership and commitment to his province and his community that will be missed by all who have known and benefited from his drive and his passion," Graham said.

Irving's life took a dramatic turn in 1982 when he was kidnapped and held against his will for several hours. He was not harmed in the incident and was eventually released but those who new the industrialist say the experience taught him about his own mortality.

A funeral will be held Saturday in Saint John for the late businessman.

He is survived by his wife, three children and six grandchildren.

With a report from CTV Atlantic