John Halenko was born in Hamilton ON and grew up in the Niagara peninsula. Campbell Scott, a Niagara-based sculptor and printmaker was his art instructor in high school. He attended the Ontario Collage of Art and Design (then OCA) in the early seventies when Roy Ascott was appointed the new director of the school; some notable instructors included Francois Thepot and Graham Coughtry. However, it was the colour field painters of the fifties and sixties that were his major inspirations and influence.
After OCA, Halenko moved to New York City where he began a career in commercial advertising photography. He moved back to Toronto in the late eighties continuing his photography career while resuming painting that focused heavily on exploring colour, special tensions, contrast and a playful juxtaposition.