Helwig was a long-time editor at Oberon Press, where he edited the annual anthology Best Canadian Stories. He wrote scripts for television and radio, and arts commentary for newspapers and magazines across the country. He has also taught at the penitentiary near Kingston, an experience that led to his nonfiction work A Book about Billie (1972), an assemblage of prose derived from his interviews with a convict. Helwig moved to a small village on Prince Edward Island in 1996.
Increasingly David Helwig's poetry moved from lyrics to longer narratives, starting with Atlantic Crossings (1974), 4 poems about ocean voyagers. The central poem of Book of the Hours (1979) deals with the 19th-century American writer Thomas Bulfinch and his ward, and Catchpenny Poems (1983) is a series of poetic meditations arising from 19th-century prints. A prolific poet, Helwig's collections include The Hundred Old Names (1989), The Beloved (1992), A Random Gospel (1996), and Telling Stories (2000). His long poem The Year One (2004) won the Atlantic Poetry Prize.
Along with his impressive poetic output, David Helwig continually wrote and published essays, novellas and novels. His essays have been collected in The Child of Someone (1997) and Living Here (2001). His memoir, The Names of Things, was published in 2006. David Helwig won the 2007 Matt Cohen Award for a lifetime of distinguished work.