Though Walt Whitman declared it first — “I hear America singing” — if the poet were still alive, he’d agree that there’s no greater contemporary advocate of his ethos than internationally acclaimed baritone Thomas Hampson.

Through his Hampsong Foundation and its Song of America project, the opera luminary has dedicated himself to telling “the story of our culture and nation, through the eyes of our poets and the ears of our composers.” Since the early 1990s, between his many engagements at leading opera houses, he has traveled the world as “The Ambassador of American Song.”

So it’s fitting that Hampson will join the Chicago Symphony Orchestra, under guest conductor Bramwell Tovey, for an Americana-themed program Jan. 10-12, anchored by works of Ives and Copland, and capped off by Elgar’s Enigma Variations.

The wide-ranging program, which Hampson said “surveys the American heartbeat as it were,” covers 20th century to contemporary works. It also ties in with the British-born Tovey’s fondness for American music. First up will be Charles Ives’ Variations on America, orchestrated by William Schuman, followed by Hampson and the CSO in Ives’ version of the traditional hymn At the River (arr. Adams). “Ives is a passion of mine, his songs especially,” Hampson said of the American composer (1874-1954), who spent most of his years as an insurance actuary and executive, and whose works were largely ignored in his lifetime. “There are so many orchestrated songs of his that you don’t get to hear in concert. Ives didn’t have much of a place in American life, except to the cognoscenti. For most of his existence, he was viewed as either a dilettante or a crazy man. We had to catch up to Ives. It took a while, but fast forward to now, when many of his works are regularly performed by orchestras.”

Following the Ives, Hampson will sing selections from Copland’s Old American Songs, “The Boatman’s Dance,” “Long Time Ago” and “The Golden Willow Tree,” and later, a relative rarity, Danny Deever, which Hampson calls “a wonderful Irish-style ballad,” about a deserter about to be executed for murder. Based on a poem by Rudyard Kipling, it was set to music by several composers, most notably Walter Damrosch, the Zelig of 20th century classical music (a student of conductor-composer Hans von Bülow, perhaps Richard Wagner’s greatest champion, Damrosch happened to meet steel magnate Andrew Carnegie aboard a steamship and persuaded him to build what would become the Valhalla of American culture).

Popularized by American baritone David Bispham (1857-1921), who gave the premiere of the Damrosch version in 1897, Danny Deever is hauntingly evocative. “It uses [the Civil War-era ballad] ‘When Johnny Comes Marching Home’ in the beginning,” Hampson said. “Bispham once sang it for Teddy Roosevelt, who called it his favorite song.”

Two contemporary works round out the program. Michael Daugherty’s “Letter to Mrs. Bixby” is from the song cycle Letters From Lincoln (2009), commissioned by the Spokane (Wash.) Symphony to commemorate the bicentennial of the 16th American president’s birth. “All of the text is from Abe’s letters,” said Hampson, a native of Elkhart, Ind., who grew up in Spokane. “The fifth song, ‘Mrs. Bixby,’ is a remarkable letter to a mother who lost five sons in the Civil War about her great sacrifice. It’s very moving, and I’ve never sung it and not have people’s breath taken away.”

John Corigliano’s song cycle One Sweet Morning (2010), co-commissioned by the New York Philharmonic to mark the 10th anniversary of 9/11, draws the text for its fourth movement from an unlikely source: an anti-war poem by E.Y. “Yip” Harburg, best known for his lyrics for “The Wizard of Oz” (1939). In his program notes for the work, Corigliano wrote: “ ‘One Sweet Morning’ ends the cycle with the dream of a world without war — an impossible dream, perhaps, but certainly one worth dreaming. In this short poem, Harburg paints a beautiful scene where ‘the rose will rise … spring will bloom … peace will come … one sweet morning.”

Hampson’s celebration of the American spirit has been going on since “Jesus was in short pants,” he added with typical self-deprecating wit. After three decades of his “I Hear America Singing” recitals, followed by his collaboration with the Library of Congress on the Song of America initiative (including a website, radio broadcasts and high-school curricula), Hampson introduced his latest enterprise, “Beyond Liberty,” at the Glimmerglass Festival last summer. Designed to “explore the influential people and monumental events that helped create and define ‘The Land of the Free,’ ” it consists of Hampson offering anecdotes and reading poetry, all in the cause of celebrating what it means to be an American.

“My goal is to keep these works as lively and as approachable for the widest possible audience,” he said. “I believe American culture is the best way to revitalize and celebrate the stories that make up of all of America. It’s important, especially to our youth, that we share all of these stories across cultures. They all tell us something.”

His most recent release, “Songs from Chicago,” his first project for Chicago-based Cedille Records, dovetails into this mission. It features works by five 20th-century composers associated with Chicago: Ernst Bacon, Florence Price, John Alden Carpenter, Margaret Bonds and Louis Campbell-Tipton. All of them “have distinguished themselves in history as great voices of the artistic American narrative,” he said. “I wasn’t able to get them on [the CSO] program because the works have not been orchestrated. I adore Margaret Bonds and Florence Price, who’s having a renaissance. And Ernst Bacon is like Ives; people don’t realize how important he is.”

Though he’s embraced his role as America’s troubadour, Hampson maintains a busy opera schedule. Over the next 18 months, he performs three world premieres. Most recent was the title role of Rufus Wainwright’s well-received Hadrian, about the Roman emperor and his love for the Greek youth Antinous, at the Canadian Opera Company in October. “I love the music, and I love the story,” he said. “The gay love story had not been realized onstage in this fashion before. It’s not so much that Hadrian was gay. This relationship became a life-defining experience. The depth of that love between two men was very beautiful.”

In April, Hampson will make his house debut at Houston Grand Opera in the world premiere of The Phoenix, Tarik O’Regan and John Caird’s autobiographical comedy about scoundrel turned librettist Lorenzo da Ponte, who later established New York’s first opera company. Hampson will play the elder da Ponte, with his real-life son-in-law, Italian baritone Luca Pisaroni, as the younger incarnation. And next year, Hampson will portray Johannes Vermeer in an operatic version of The Girl with a Pearl Earring.

As he approaches the fifth decade of his career, Hampson harbors no thoughts of retirement. “I love too much what I do, and I’m going to keep singing until somebody with a huge hook pulls me offstage,” he said, laughing. “When it happens, it happens. I don’t worry about it.” For now, he’s “thrilled to back in Chicago, which I consider the great American city.”