He partnered with John R. Sweney to produce and publish over 1,000 gospel hymn songs and over sixty hymnal books.

In 1855, he became involved in the Wharton Street Methodist Episcopal Church serving the choir with his musical talent and teaching Sunday school.

Beginning in 1858, Kirkpatrick began working with A.S. Jenks who helped him publish his first collection of hymns, Devotional Melodies, in 1859.

His involvement with the Harmonia Society introduced him to another man, Dr. Leopold Meignen, under whose tutelage he devoted himself primarily to the study of music focusing on theory and composition.

Over the next 11 years, Kirkpatrick was elected lead organist for the Ebenezer Methodist Episcopal Church, studied the pipe organ, continued in vocal lessons, and began publishing more and more hymns.

The death of Kirkpatrick’s wife in 1878 acted as a catalyst in his life to give up the trade and devote himself fully to music and composition.

William feared that this young man did not really know Christ and so he began to pray that God would somehow get a hold of the soloist's heart.

When the preacher gave the altar call at the end of the night, the soloist got up and went to the front of the tent and accepted Jesus into his heart.