Before beginning to train in speed walking, Jobin had engaged in hockey, running, snowshoeing, cycling, and had competed in canoe portaging competitions. In 1958, at the age of 16, he participated in his first event, a 10,000 metre race. A few months later, he participated in Montréal's 12 mile Classique du Parc Lafontaine, and soon joined the Francs-Amis, an active sports club in the city.
Hooked on running, he was in most road racing competitions in Québec during the 1960s. As it was difficult for runners to train in winter, Jobin took up snowshoeing in 1962. He met with success in this sport from the outset, and was named rookie of the year by the Canadian Snowshoer's Union that year.
In 1967, Marcel Jobin received a postcard from Yvon Groulx, an athlete in the Francs-Amis who was participating in the Winnipeg Pan American games in race walking. This postcard would change the course of Jobin's life, and a few weeks later, Groulx introduced his friend to this demanding sport. Jobin quickly mastered the technique, and by 1968 his ten years of athletic training served to make him a high calibre competitor.
His first event was in the Eastern Canadian championships in Toronto. He just missed qualifying for the Olympic Games in Mexico by finishing in fourth place.
In his first complete season (1969), he became the provincial champion in the 20 km, won his first Eastern Canadian championship, and finished third in the American championships in Boston. The following year he won the first in a series of Canadian championship titles. In 1971, he took part in the PAN-AMERICAN GAMES in Cali (Columbia) finishing fourth in the 20 km race and sixth in the 50 km race. He was in these games again in Mexico (1975), San Juan (1979), and Caracas (1983).
In 1972, with the 20 km Canadian championship title in hand, he qualified for the 47 member Canadian track and field team. Unfortunately, several weeks into the Games, he was one of ten team members who were cut for budgetary reasons. In spite of this blow to his morale, and after struggling with the idea of quitting, he doggedly pursued his career as an amateur while continuing to work to support his family.
Four years later, he at last competed in his first Olympic Games in the 20 km event. When he crossed the finish line before a packed audience in Montréal's Olympic Stadium, he understood that he had just realized his dream, despite placing 23rd. He qualified for the Moscow Olympics (1980), but was disappointed once more when Canada decided to boycott these games.
In 1978, Jobin was in the COMMONWEALTH GAMES in Edmonton, and in 1982, he won a silver medal at the games in Brisbane, Australia. He again savoured the Olympic experience in Los Angeles in 1984, where he placed 21st in the 20 km. After this, he retired from competition.
During the seventeen years of his career, this athlete from Saint-Boniface was a Canadian champion fifteen times in the 20 km and successfully retained the title for thirteen consecutive years (1972 to 1984). Through the years, he accumulated Canadian titles and scored nearly one hundred records in all distances: indoors in the 1500 metres, the mile, and the 3 km; outdoors in the 5,000 and 10,000 metres and in the 25, 30 and 50 kilometres.
His best 20 km performance (1:24:08) was realized in his qualification for the 1984 Los Angeles Olympics. Furthermore, he was the first Canadian athlete to walk 50 km in under four hours.
After 2000, Marcel Jobin resumed competition in the veteran's class in running and race walking events. In 2012, at the age of 70, he won the world title in the 70-75 year age category in the 3 km indoor event at Jyväskylä, Finland.
This great Canadian walker was recognized for his outstanding career with the prix Maurice-Richard from the Société Saint-Jean-Baptiste de Montréal (1980). In 1993, he was inducted into the QUÉBEC SPORTS HALL OF FAME. Ten years later, he won the Queen Elizabeth II Golden Jubilee Medal. Since 1996, hundreds of runners have taken part in the Marcel Jobin Demi-marathon, a racing event in his honour held at Yamachiche, in Québec's Mauricie region.