The Willys-Knight employed a Knight sleeve valve engine, generally four- and six-cylinder models.

In 1915, Willys moved assembly of the Willys-Knight to Toledo, Ohio, but continued manufacturing the engines in Elyria.

Willys also purchased Stearns-Knight of Cleveland, Ohio, which also used a sleeve valve Knight Engine, making that marque the crown jewel in his growing automotive empire.

Willys-Knight production ended in November 1932 (model year 1933) when the company, in receivership, stopped building higher priced cars, and instead focused on the manufacture of the inexpensive but durable Willys 77.

Seven Willys-Knight vehicles including two large trucks and a touring car were used on the Martin and Osa Johnson photographic safari in the remotest areas of Africa.