In 1933, Ferdinando Innocenti set up a company in Milan, Innocenti Società Generale, to produce large-size components for the metallurgical plant and rolling mill industry. After the Second World War, the company expanded its product portfolio to include the manufacture of motor scooters (Lambrettas) and cars. In 1958, Innocenti was awarded the biggest contract in the company's history: the construction of an iron and steel plant in Venezuela. The design and construction of its rolling mills was handled by Schloemann AG. Innocenti has built a large number of continuous casters for Concast.

The Innocentis sold the family-owned business in 1972. The state-run IRI group took over the Mechanical Engineering division and changed the name to Innse Innocenti Sant'Eustacchio. In 1985, the company became part of Italimpianti within the IRI group. This company was acquired by Mannesmann Demag in 1996.

With the merger of Mannesmann Demag Metallurgie and SMS Schloemann-Siemag, Innse joined SMS in 1999 under the name of SMS Demag. The manufacturing division was sold at the beginning of the 2000s. Known from 2009 as SMS Innse, the company's operations were concentrated on the design, construction, and marketing of plant and machinery for processing steel and nonferrous metals.

The Italian locations of SMS group were merged on January 1, 2019, and the name Innse disappeared. SMS group S.p.A. designs and manufactures plant and machinery from the Electrics/Automation, Metallurgical and Environmental Technology, Processing Lines and Furnace Technology, Flat Rolling Plants, and Long Products business units.