Two-time US Poet Laureate Stanley Kunitz said of Roethke, "The poet of my generation who meant most to me, in his person and in his art, was Theodore Roethke."
In a Spring 1976 interview in the Paris Review (No. 65), James Dickey defended his choice of Roethke as the greatest of all American poets. Dickey states: "I don't see anyone else that has the kind of deep, gut vitality that Roethke's got. Whitman was a great poet, but he's no competition for Roethke."
In his book The Western Canon; The Books and School of the Age, (1994) Yale literary critic Harold Bloom cites two Roethke books, Collected Poems and Straw for The Fire, on his list of essential writers and books. Bloom also groups Roethke with Elizabeth Bishop and Robert Penn Warren as the most accomplished among the "middle generation" of American poets.
In her 2006 book, "Break, Blow, Burn: Forty-three of the World's Best Poems," critic Camille Paglia includes three Roethke poems, more than any other 20th-century writer cited in the book.
The Poetry Foundation entry on Roethke notes early reviews of his work and Roethke's response to that early criticism:
W. H. Auden called [Roethke's first book] Open House "completely successful." In another review of the book, Elizabeth Drew felt "his poems have a controlled grace of movement and his images the utmost precision; while in the expression of a kind of gnomic wisdom which is peculiar to him as he attains an austerity of contemplation and a pared, spare strictness of language very unusual in poets of today." Roethke kept both Auden's and Drew's reviews, along with other favorable reactions to his work. As he remained sensitive to how peers and others he respected should view his poetry, so too did he remain sensitive to his introspective drives as the source of his creativity. Understandably, critics picked up on the self as the predominant preoccupation in Roethke's poems.
Roethke's breakthrough book, The Lost Son, also won him considerable praise. For instance, Michael Harrington felt Roethke "found his own voice and central themes in The Lost Son" and Stanley Kunitz saw a "confirmation that he was in full possession of his art and of his vision." In Against Oblivion, an examination of forty-five twentieth century poets, the critic Ian Hamilton also praised this book, writing, "In Roethke's second book, The Lost Son, there are several of these greenhouse poems and they are among the best things he wrote; convincing and exact, and rich in loamy detail."
In addition to the well-known greenhouse poems, the Poetry Foundation notes that Roethke also won praise "for his love poems which first appeared in The Waking and earned their own section in the new book and 'were a distinct departure from the painful excavations of the monologues and in some respects a return to the strict stanzaic forms of the earliest work,' [according to the poet] Stanley Kunitz. [The critic] Ralph Mills described 'the amatory verse' as a blend of 'consideration of self with qualities of eroticism and sensuality; but more important, the poems introduce and maintain a fascination with something beyond the self, that is, with the figure of the other, or the beloved woman.'"
In reviewing his posthumously published Collected Poems in 1966, Karl Malkoff of The Sewanee Review wrote:
Though not definitive, Roethke: Collected Poems is a major book of poetry. It reveals the full extent of Roethke's achievement: his ability to perceive reality in terms of the tensions between inner and outer worlds, and to find a meaningful system of metaphor with which to communicate this perception.... It also points up his weaknesses: the derivative quality of his less successful verse, the limited areas of concern in even his best poems. The balance, it seems to me, is in Roethke's favor.... He is one of our finest poets, a human poet in a world that threatens to turn man into an object.
In 1967 Roethke's Collected Poems topped the lists of two of the three Pulitzer Prize poetry voters; Phyllis McGinley and Louis Simpson. However the group's chairman, Richard Eberhart, lobbied against Roethke on the grounds that the award should go to a living poet. It would have been Roethke's second Pulitzer Prize.