He was 88.
Bobak, of Fredericton, had been diagnosed with throat cancer during the summer.
He died Monday night at the Saint John Regional Hospital.
Bobak was painting as recently as last winter, having contributed a large canvas to the Aspects of Fredericton exhibition at Gallery 78.
Bobak and his wife, Molly Lamb, were both enlisted by the federal government to detail its efforts in the Second World War after placing first and second in an art competition in 1944.
Bobak, who was only in his early 20s, was the country's youngest war artist.
He had recently graduated from art school in Toronto and joined the army as part of the Royal Canadian Engineers.
According to The Military Museums' website, Bobak later reflected that becoming a war artist may have saved his life because most of the company he had been with was killed during their first day in Europe.
Bobak documented war scenes in Belgium, Holland and France, including Normandy.
In a 2002 interview with the CBC, he described the dual role of the war artist.
"There are two ways of looking at war art. One is a historical thing, and the other is a personal creative thing. And actually being a war artist combines the two," he said.
"Either you're making a document, or you're also trying to express yourself as an individual."
In 2006, Bobak told CBC News he was happiest when he was fishing and gardening, but he was also proud of his legacy as a painter.
"Being well-recognized as an artist is something that I'm happy about and [I'm] hoping to leave a small mark, or any kind of mark, enriching the cultural life of the country," he said.
Numerous prestigious awards
Bobak was born in Wawelowska, Poland and emigrated to Canada in 1927.
He began studying art at the age of 13 in Toronto under Arthur Lismer, a member of the Group of Seven and subsequently studied under future war artists, such as Carl Schaefer and Charles Goldhammer.
Bobak and his wife moved to Fredericton in 1960 after he was appointed artist-in-residence at the University of New Brunswick in 1960.
Bobak also served as the director of the UNB Art Centre from 1962 until his retirement in 1986.
He received several prestigious awards and honours over the years, including being named a Member the Order of Canada in 1995, along with his wife.
"Their energy and enthusiasm as teachers, fund-raisers and arts advocates have helped create a climate for artistic and cultural growth in New Brunswick and earned them the respect of the academic world and the community beyond," according to a statement by the Governor General of Canada.
Bobak's works are found in collections across Canada.
Many of his war paintings are part of the collection at the Canadian War Museum in Ottawa.
Bobak participated in more than 250 group exhibits and had more than 80 one-man shows around the world.