A classical vocalist, her repertoire encompassed opera, operetta, musical theatre, art songs, and popular ballads; all genres which were in demand among American consumers during that period in history.

[5] By 1910 she had moved to New York City[6] and was working as a singer at Brick Presbyterian Church where she was a highly paid vocalist for several years.

[19] While studying with Bellinger, Kimball became a paid resident soprano soloist at the Tabernacle Presbyterian Church in Indianapolis,[4] and made her professional concert debut at the Bloomington, Indiana, May Festival in 1906.

[6] By March 1910 Agnes Kimball had left Pittsburgh, and moved to New York City by herself to pursue her singing career.

[24] She commanded one of the highest salaries for a church vocalist in the country while she was singing at Brick Presbyterian,[4][8] and was a resident singer there from 1910 to 1914.

[24] Conductor and composer Victor Herbert, who was a leading force in American operetta, attended one of the Chautauqua concerts in which Kimball was a soloist.

Impressed with her singing, he offered her a position as the lead soprano in a concert tour with his professional light opera orchestra.

[20] In 1911–1912 Kimball toured the United States singing mainly excerpts from operettas in two seasons of concerts with the Victor Light Opera Orchestra.

The other members of that quartet included tenor Reed Miller and his wife, contralto Nevada Van der Veer.

In 1911 she was the soprano soloist in George Frideric Handel's Messiah with the Apollo Chorus of Chicago at the Auditorium Theatre.

[4] At the time of her death, the Detroit Free Press described her as a "singer at the forefront of church soloists" who had "sung for all the prominent record companies" and earned a "national reputation".

The first of these was "Gems from Florodora" which consisted of selections from the opera of that name by Leslie Stuart; among them the famous double sextet, "Tell me pretty maiden".

[41] Kimball was a member of the VTMC's "Victor Opera Quartet" with whom she recorded several solo arias as well as works for multiple singers.

These included the arias "Un bel dì, vedremo" (sung in English as "Some day he'll come") from Giacomo Puccini's Madama Butterfly (1911),[42] and "Spring Song" from Herbert and Joseph Redding's Natoma (1912);[43] and the quartet "Bella figlia dell'amore" from Act III of Verdi's Rigoletto.

She recorded several more songs that year with Columbia, including "Love is a story that's old" from Victor Herbert's operetta The Madcap Duchess; the duet "You're here and I'm here" from Jerome Kern's musical The Laughing Husband (sung with tenor Charles W. Harrison); and the duet "Come on over here" from the Leo Fall and Harry B. Smith musical The Doll Girl (also sung with Harrison).