[1] In 1856 he returned to Portland, Maine, and in the early 1860s he secured a contract producing uniform coats and pants for the Union Army.

[3] Around 1870, Deering left that business and partnered with Elijah Gammon, providing $40,000 in funding for the production of a horse-drawn grain harvester developed by brothers William and Charles Marsh.

[8] William Deering financially supported several institutions of Chicago, the Northwestern University, the Garrett-Evangelical Theological Seminary, and the Wesley Hospital among them.

[9] After Deering retired in 1901 he spent a large part of each year at his winter home in Coconut Grove, Florida.

In the late 1890s, Deering scouted territory in Southeast Missouri for timber and purchased 60,000 acres of land in Pemiscot and Dunklin Counties.