[1] His paternal grandfather was Amos Warner, who fought in the American Revolutionary War.

[2] In 1847, he came to Rochester as an apprentice to one of his uncles, Merwin Austin, for whom he worked as a draftsman.

[3] He was soon made a partner in his uncle's business, which as Austin & Warner existed from about 1855 to 1858.

[4] Warner then established an independent practice until 1867 when he partnered with Charles Coots under the firm name of Andrew J. Warner & Co.[5] After this he had an independent practice, then from 1875 to 1877 partnered with James Goold Cutler (1848-1927) in a firm known as Warner & Cutler.

Together, they were the parents of two sons:[8] Warner died in Rochester on September 4, 1910, and is buried in Mount Hope Cemetery.