Halleck had quickly become one of the most well-known humorists and poets of his day. By 1849, he was able to move back from New York to his home town in Guilford, Connecticut, thanks to an annuity left to him by the estate of his former employer John Jacob Astor. Unmarried himself, he spent his final years with his unmarried sister, ignoring requests for public readings. Frequently sick, he expected his death as early as 1860. When he was laid to rest at Alderbrook Cemetery, his funeral procession was a marvelous spectacle.
Among Halleck's final works was a book-length poem, Young America, which described the shaping of the country through an allegory about a boy. From that poem, written at the end of the Civil War:
How sweetly the Boy in the beauty is sleeping
Of Life's sunny morning of hope and of youth,
May his guardian angels, their watch o'er him keeping,
Keep his evening and noon in the pathways of truth.
Ah me! what delight it would give me to wake him,
And lead him wherever my life banners wave,
O'er the pathways of glory and honor to take him,
And teach him the lore of the bold and the brave;
And when the war-clouds and their fierce storm of water,
O'er the land that we love their outpourings shall cease,
Bid him bear to her Ark, from her last field of slaughter,
Upon Victory's wings, the green olive of Peace;
And when the death-note of my bugle has sounded,
And memorial tears are embalming my name,
By young hearts like his may the grave be surrounded
Where I sleep my last sleep in the sunbeams of fame.
Summoned to duty by his charger's neighs,
The only summons that his pride obeys,
He bows his farewell blessing, and is gone,
In quiet heedlessness the Boy sleeps on.