Hilbert's third collection, "Caligulan", published by Measure Press in 2015, was selected as winner of the 2017 Poets' Prize. Rowan Ricardo Phillips wrote “moved by beauty, attuned to the sublimity of natural things, livened by paradox, coaxed into song by pentameter, Ernest Hilbert’s rich new book covers more emotional ground than a reader has any right to expect.” Rachel Hadas wrote that "the poems in "Caligulan" fashion a stern, witty, and often poignant music out of seemingly unpromising elements courageously glimpsed, combined, or imagined." His fourth collection, "Last One Out", was published by Measure Press in 2019. Poet Ilya Kaminsky wrote that “"Last One Out" is a very beautiful book. It sings.” A. E. Stallings wrote in a review that "Hilbert is enjoying, mid-career, a new formal freedom, and with it, wider territory to cover, or perhaps vice versa," adding "here a certain amount of youthful edge and swagger has been worn away, but is replaced by mastery, depth, and mellowed sweetness; the words I’m reaching for, I realize, might just as well describe single malts: aged and peaty, smoky and complex."