Ryan, a 63-year-old California native, is to begin her duties in the fall, opening the library's annual literary series Oct. 16 with a reading of her work.
She also will be a featured guest at the Library of Congress National Book Festival in the Poetry pavilion Sept. 27 on the National Mall in Washington, Billington said.
"Kay Ryan is a distinctive and original voice within the rich variety of contemporary American poetry," Billington said in a statement Thursday. "She writes easily understandable short poems on improbable subjects. Within her compact compositions there are many surprises in rhyme and rhythm and in sly wit pointing to subtle wisdom."