Most notably, Galloway was the official organist for the 1904 Louisiana Purchase Exposition in St. Louis, where he debuted the great organ in Festival Hall (now preserved as the nucleus of the Wanamaker Organ at Macy's Center City in Philadelphia) which was the largest organ in the world at that time. Though he composed numerous works as a young man, Galloway later admitted in a letter to W.H. Pommer, “I cannot believe that it was ever meant for Charles Galloway to compose.” He also served as the conductor of the most respected men's and women's choral ensembles in the St. Louis area: the Apollo Club of St. Louis and the Morning Choral Club, respectively. As an educator, Galloway taught at various institutions, including the Strassberger Conservatories of Music, Washington University, and Lindenwood College.) In addition, he had a large number of private keyboard students, many of whom went on to become church musicians and educators.