[1] At École Centrale Paris, he learned the latest iron construction techniques as well as the classical functionalist doctrine of Jean-Nicolas-Louis Durand (1760–1834) - Professor of Architecture at the Ecole Polytechnique.

[7] In 1861, he returned to the US to join the Union Army as an engineer in the Civil War, designing fortifications for Generals Sherman and Grant.

[1] After the war, in 1867, Jenney moved to Chicago and began his own architectural office, which specialized in commercial buildings and urban planning.

In later years future leaders of the Chicago School like Louis Sullivan, Daniel Burnham, William Holabird, and Martin Roche, performed their architectural apprenticeships on Jenney's staff.

Later, he solved the problem of fireproof construction for tall buildings by using masonry, iron, and terra cotta flooring and partitions.

Jenney applied his new idea to the construction of the Home Insurance Building, the first skyscraper in the world, erected in 1884 at the corner of LaSalle and Monroe Streets in Chicago.

Another source cites the inspiration for the steel skyscraper as coming from vernacular, Philippine architecture, where wooden framed construction gave Jenney the idea.

After Jenney's death, his ashes were scattered over his wife's grave, just south of the Eternal Silence section of Uptown's Graceland Cemetery.