Natasha Trethewey, an Emory University writing professor and author of three poetry collections, including “Native Guard,” which won the 2007 Pulitzer Prize in poetry, has been named the 19th Poet Laureate Consultant in Poetry, the Library of Congress announced Thursday.

Trethewey, whose poetry flows from traditional rhyme to free verse, often evokes paintings and photographs to explore what she calls the “mind’s architecture” and “the cultural memory of a people.”

Trethewey, 46, who has been the Poet Laureate of Mississippi since January, says that she’s excited and nervous and that “the position of the laureate is one where you can really do significant things.”

One role of the poet is to record “across time and space what speaks to us about an historical moment and people’s responses to the historical moment in which they live. Poetry can do that. It can connect us to people distant and different from us. It can remind us of how we are alike.”

Her appointment begins in September, the same month her fourth poetry collection, “Thrall,” will be published, and opens the library’s annual literary season. Trethewey, who was born in Gulfport, Miss., will be one of the youngest poet laureates, according to Librarian of Congress James H. Billington, and one of the rare poet laureates to take up residence in Washington, which she will do from January to May.

Billington first heard Trethewey reading at a National Book Festival several years ago and was “immediately struck by a kind of classic quality with a richness and variety of structures with which she presents her poetry.” And by the way “she intermixes her story with the historical story in a way that takes you deep into the human tragedy of it,” he said.

In 1985, Trethewey’s mother was killed when Trethewey was a 19-year-old student at the University of Georgia. When she began writing the elegies for her mother that make up the opening section of “Native Guard,” “I did think that these were so personal that they couldn’t speak to anyone else. Even though I knew intellectually that was not true,” Trethe­wey says. “I was reminded that it is only through the particular that we get to the universal.”

On Tuesday, the anniversary of her mother’s death, as she was anticipating the announcement of her appointment, Trethewey says she was also noting how “the history of my own life is to see how moments of joy often overlap with things that are quite difficult.”

In taking about why people come back to the language of poems, Billington cites Trethewey’s poem “Again, the Fields.”

The wheat falls beneath his scythe —

A language of bounty —

the swaths like scriptures on the field’s open page.

Boundless, the wheat stretches beyond

the page as if toward a distant field —

“It’s never overstated,” he says. “It reminds you that the experience of great art, of great poetry, is something that stretches beyond the frame it comes to you in.”