In 1922, Rudolf Lehni senior (1885–1956), who was born in Basel, opened a sheet metal workshop not far from the Kunsthaus Zurich. As a craftsman interested in culture, he had already cultivated contacts with the artistic avant-garde in Berlin during his travelling days. His workshop soon became a meeting place for artists. After setting up shop in Zurich Hottingen, his workshop developed into a renowned business with 40 employees. Lehni also occasionally carried out metalwork for the Schauspielhaus (playhouse) in Zurich.

The international artist, graphic designer and architect Max Bill commissioned Lehni to make his famous "Wellrelief" in 1932. Architect Willy Boesiger was also a customer: For the chess players in his "Café Select", he designed a folding table in 1935, which was produced by Lehni. Rudolf Lehni junior, a regular guest at the meeting place for Zurich's non-conformists, later included the table in the Lehni collection.

Rudolf Lehni senior died in 1956, and shortly afterwards his son took over the company’s management. Rudolf Lehni junior (1927-1981) greatly expanded the company in the following years and shifted their production towards industrial manufacturing. He developed a new bending technique for sheet metal, for example, which made precise processing possible and made the company well-known in architectural circles. Lehni worked regularly with his friend, the architect Ernst Gisel, whom he got acquainted with because their families lived in the same neighbourhood.

In addition to working in the sheet metal workshop, Rudolf Lehni taught materials science and metalworking at the Kunstgewerbeschule (School of Arts) in Zurich. It was there that he met the artist and designer Andreas Christen (1936-2006), who was already experimenting with aluminium. Mediated by Max Bill, the famous Aluminium Shelf was created for the 1964 Expo (Swiss National Exhibition) in Lausanne and was subsequently added to the collection. Lehni and Christen then fostered a collaboration that lasted over 40 years. Christen designed the main part of the Lehni furniture collection until his death in 2006.

In the seventies, the furniture trade became an important pillar of the company. Lehni decided to relocate production to Dübendorf. He commissioned Ernst Gisel Architekt to design the new factory building, which was completed in 1975. The move boosted the serial production, and the collection continued to grow.

Lehni's ties to the Zurich art scene favoured new collaborations with artists – including Sol LeWitt, for whom Lehni realised several artworks, such as "Cubes with Hidden Cubes". After Rudolf Lehni's untimely death in 1981, his wife Doris Lehni-Quarella (1944-1998) took over the company’s management. The photographer played a key role in shaping the fortunes of the company. Together with Andreas Christen, she continued to further develop the furniture product range, creating classics such as the Cabinet and Bed 1.

The furniture objects by the artist Donald Judd, which he had manufactured by Lehni starting in 1984, were a special case. The collaboration resulted in 15 different pieces of furniture, available in powder-coated aluminium, sheet copper, or brass. All the pieces are numbered and stamped.

Doris Lehni-Quarella documented the growing collection in powerful photographs. The simple designs also reflect the industrial manufacturing process. In the 1990s, seating furniture was also added to the collection, for example the Anodised Chair or Armchair, which were designed for both indoor and outdoor use.

The unexpected death of Doris Lehni-Quarella in 1998 marked another turning point in the history of the company.

Doris Lehni-Quarella left the company to her nephew Antonio Monaci, who studied art and architecture at the University of Florence. With Heinz and Ursula Menet, who were trusted employees of Doris Lehni-Quarella, Antonio Monaci has since continued to lead the company in the direction set by the previous generation. The architect with a keen interest in design has created several pieces for Lehni, such as the Sofa (2008). Other creations that emerged under the auspices of the Menet siblings were the Office Shelf, specifically tailored to the needs of workspaces, and the last design by Andreas Christen, the Modular Cabinet (2005). The collaboration with new designers results in straightforward pieces in the spirit of the Lehni collection.

Since 2014, Lehni has also been producing custom-made kitchens made of aluminium, in close cooperation with architects and leading kitchen appliance manufacturers.

The year 2022 marks both Lehni’s anniversary as well as a new beginning: Since then, owner Antonio Monaci and his wife Benedetta Agostini have jointly managed the company.