In 1919, the company entered into a partnership with an artisan from Limoges, Jean Mondot, who had started a small factory in Exideuil making electric switches using porcelain and boxwood.

In 1949, following a factory fire, the decision was made to exclusively concentrate on electrical wiring devices (switches and sockets).

Since then, Legrand has made more than 100[12] targeted acquisitions becoming a large and diversified maker of electrical and digital building infrastructures and connected devices with more than 300,000 product items.

[24][25] 2003: Purchase of the entire share capital by investment funds Kohlberg Kravis Roberts (KKR) and Wendel Investissement.

[26] 2005: Acquisition of ICM Group (KZ and Cablofil brands), world leader in wire mesh cable trays.

2 in electrical wiring devices in Australia, and Kontaktor, the leading Russian manufacturer of power circuit breakers.

1 in Brazil producer of residential access control (entry phones); Estap, the Turkish leader in VDI enclosures, and Electrak, UK specialist in ground-laid cable trays.

2010: 2011: Legrand acquired the American company Electrorack,[32] the French leader in independent living aids for dependent people.

[37] The same year, Legrand announced the acquisition of the French Intervox,[38] as well as Tynetec, a UK-based company specializing in assisted living systems.

[39] 2014: In March, Legrand signs an agreement to acquire Lastar, Inc. a Moraine, Ohio cabling and connectivity products supplier which, in 2013, reported more than $140 million in revenue and had nearly 1,000 total employees in nine locations in the U.S., Europe and Asia.

The same year, Legrand acquires a stake in Netatmo, a French start-up based in Boulogne-Billancourt (Paris area) and specialized in Internet of Things (LoT).

[45][46][47] Same year, Legrand acquired a majority stake at Debflex, a leading French company specialized in the production of electrical equipment.

[49] Legrand acquired leading U.S. data center power system manufacturer American Universal Electric Corporation headquartered near Pittsburgh, Pennsylvania,[50] and Jobo Smartech, a Chinese company of connected controls for hotel rooms.

[55] 2021: Acquisition of Ensto Building systems division of Ensto, a private electrification, lighting and EV charging manufacturer based in Finland, optical networking components provider Champion One, passive data communication specialist Compose, and Borri, a global provider of and single phase and three phase UPS systems.

[57][58] Simultaneously, in a post-pandemic context, Legrand established record results, notably in the Data Center, Connected Products and Energy Efficiency sectors.

If minority stakeholders and eventually the company's management opposed the bid, a veto from the European Commission about competition issues would cause the transaction to definitely fail.

[89] Legrand proposes services in home automation such as products with the Netatmo technology embedded used to manage operations on a remote control of electrical and heating appliances.

[93] In 2020, during the CES (Consumer Electronics Show) Legrand presented new products with energy efficiency for home automation.

[94] Legrand is present in the data center sector, notably with the following products: VDI (Virtual desktop infrastructure), PDUs (Power distribution unit), etc.