Maxine Kumin described Sexton's work: "She wrote openly about menstruation, abortion, masturbation, incest, adultery, and drug addiction at a time when the proprieties embraced none of these as proper topics for poetry." Some critics regard her dependence on alcohol as compromising her last work.
However, other critics see Sexton as a poet whose writing matured over time.
Sexton later studied with Robert Lowell at Boston University alongside distinguished poets Sylvia Plath and George Starbuck.
Sexton's poetic career was encouraged by her mentor W. Snodgrass, whom she met at the Antioch Writer's Conference in 1957.
She had two older sisters, Jane Elizabeth (Harvey) Jealous (1923–1983) and Blanche Dingley (Harvey) Taylor (1925–2011). In 1945 she enrolled at Rogers Hall boarding school, Lowell, Massachusetts, later spending a year at Garland School.
She had two children named Linda Gray (1953) and Joyce Ladd (1955). The first poetry workshop she attended was led by John Holmes.
His poem "Heart's Needle" proved inspirational for her in its theme of separation from his three-year-old daughter.
She won the Pulitzer Prize for poetry in 1967 for her book Live or Die.Within twelve years of writing her first sonnet, she was one of the most honored poets in America: a Pulitzer Prize winner, a fellow of the Royal Society of Literature and the first female member of the Harvard chapter of Phi Beta Kappa.On October 4, 1974, Sexton had lunch with Kumin to revise galleys for Sexton's manuscript of The Awful Rowing Toward God, scheduled for publication in March 1975 (Middlebrook 396).The Awful Rowing Toward God and The Death Notebooks are among her final works, and both center on the theme of dying.(Transformations was used as the libretto for the 1973 opera of the same name by American composer Conrad Susa.) Later she used Christopher Smart's Jubilate Agno and the Bible as the basis for some of her work.