On his return from Europe, Root began composing and publishing sentimental popular songs, a number of which achieved fame as sheet-music, including those with
Fanny Crosby:
The Hazel Dell,
Rosalie the Prairie Flower, ''There's Music in the Air'' and others, which were, according to Root's
New York Times obituary, known throughout the country in the
antebellum period. Besides his popular songs, he also composed gospel songs in the
Ira Sankey vein, and collected and edited volumes of choral music for singing schools, Sunday schools, church choirs and musical institutes. Root assisted
William Bradbury in compiling
The Shawm in 1853, a collection of hymn tunes and choral anthems, featuring the cantata
Daniel: or the Captivity and Restoration. The cantata was a collaboration between Root and Bradbury musically, with text by Fanny Crosby and C.M. Cady. In 1860 he compiled
The Diapason: Collection of Church Music. He also composed various sacred and secular
cantatas including the popular
The Haymakers (1857). Root's cantatas were popular on both sides of the Atlantic throughout the 19th century. His first cantata,
The Flower Queen: or The Coronation of the Rose, was composed in 1851 with libretto by Fanny Crosby, and gained immediate success in singing schools across the United States.
The Flower Queen has been regarded as the first secular cantata written by an American. He wrote the first song concerning the war,
The First Gun is Fired, only two days after the conflict began with the bombardment of
Fort Sumter. He ultimately had at least 35 war-time "hits", in tone from the bellicose to the ethereal. His songs were played and sung at both the home front and the real front.
Tramp, Tramp, Tramp became popular on troop marches, and "Battle Cry of Freedom" became well-known even in England. After the war, he was elected as a 3rd Class (honorary) Companion of the
Military Order of the Loyal Legion of the United States. Root's songs, particularly "The Battle Cry of Freedom", were popular among Union soldiers during the war. According to Henry Stone, a Union war veteran recalling in the late 1880s: ==Later life and death==