The poem is written in unrhymed dactylic hexameter, possibly inspired by Greek and Latin classics, including Homer, whose work Longfellow was reading at the time he was writing "Evangeline." He also had recently, in 1841, translated "The Children of the Lord's Supper," a poem by Swedish writer Esaias Tegnér, which also used this meter. Evangeline is one of the few nineteenth-century compositions in that meter which is still read today.
Some criticized Longfellow's choice of dactylic hexameter, including poet John Greenleaf Whittier, who said the poem would have been better in a prose style similar to Longfellow's Hyperion. Longfellow was conscious of the potential criticism. When sending a copy of the poem to Bryan Procter, Longfellow wrote: "I hope you will not reject it on account of the metre. In fact, I could not write it as it is in any other; it would have changed its character entirely to have put it into a different measure." Even Longfellow's wife Fanny defended his choice, writing to a friend: "It enables greater richness of expression than any other, and it is sonorous like the sea which is ever sounding in Evangeline's ear." As an experiment, Longfellow reassured himself that he was using the best meter by attempting a passage in blank verse. Even so, while looking over the proofs for a second edition, Longfellow briefly wished he had used a different poetic structure:
It certainly would be a relief to the hexameters to let them stretch their legs a little more at their ease; still for the sake of uniformity I believe they must still sit a while longer with their knees bent under them like travelers in a stage-coach.
The name Evangeline comes from the Latin word "evangelium" meaning "gospel." The Latin word itself is derived from the Greek words "eu"—"good"—and "angela"—"news".