[1][2] In January 1864, at the age of 13, he appeared with the Bury St. Edmunds Athaenaem Choral Society in its production of Handel's Judas Maccabaeus, the Norfolk Chronicle noting the "strength in the voice of the young chorister from Norwich Cathedral (Master A. Mann), whose delightful and judicious singing surprised the audience".
[1] Early in his career Mann served as organist of St. Peter's Collegiate Church, Wolverhampton (1870–1871), St. Michael's Church, Tettenhall (1871–1875), and Beverley Minster (1875–1876)[4] before being appointed Director of Music at King's College Chapel, Cambridge, in 1876, a position he held for over 50 years until his death in 1929.
Mann did much to raise the reputation of the Choir of King's College to the position of excellence it continues to enjoy today, and was renowned as a vocal trainer whose methods helped to enhance the quality of singing at English cathedrals and choral foundations generally.
In 1888 he published his own edition of "Spem in alium" by Thomas Tallis, which was the first publication ever made of the forty-part motet.
He also revised and edited a Psalter with psalm settings pointed for chanting in the Anglican style, which was published in 1912.