Howarth graduated with one of the first cohorts of students from the newly inaugurated Faculty of Fine Arts at the University of Victoria in 1970. He decided to become a full time artist in 1973, after working as an art critic for the Montreal Star and the Victoria Daily Times in 1971, and travelling and studying in Europe through 1972. He emerged rapidly as an important name in Canadian painting in the 1970s with numerous group and solo shows across the country. It was at this time that he began creating paintings in the tondo shape, and those works remain some of his most iconic. Howarth was elected a Fellow of the Royal Canadian Academy of Arts in 1978. On an international level, Howarth represented Canada at the Sao Paulo Art Biennale in 1982 and also at Expo ‘86 with his digital graphic art.