[4] Production was announced in late 2019 following the success of Ben Lewis's book The Last Leonardo: The Secret Lives of the World’s Most Expensive Painting.

[5] The opening introduces two American art dealers, Alexander Parish and Robert Simon, who buy a painting titled "After Leonardo" at a 2005 auction in New Orleans for $1,175.

[6] They show it to the New York art restorer Dianne Modestini, who cleans away the overpainting and discovers that the position of a thumb has moved (i.e. pentimento), suggesting the painting is an original.

In 2008, they present the work to a curator at the National Gallery, Luke Syson, who asks five Leonardo experts[a] including Maria Teresa Fiorio and Martin Kemp to view the picture.

[6] In 2017, Rybolovlev hires Christie's to sell his entire portfolio and they market the painting as the "male Mona Lisa" and create a promotional video that includes Leonardo DiCaprio.

In advance of the exhibition, bin Salman visits the Louvre with Emmanuel Macron and a publication appears in the museum's shop that authenticates the painting as being by Leonardo.

[11][13] In October 2019, it was announced that Andreas Koefoed would direct a film about the painting, The Lost Leonardo, with Dogwoof set to distribute in the United Kingdom.

[11] Koefoed told The Guardian that the tone of the film was to be "The Emperor's New Clothes", "puffed up institutions and authorities declare they've discovered a Leonardo, only to be exposed and mocked".

[4] In March 2021, Sony Pictures Classics acquired worldwide distribution rights (excluding the United Kingdom, France and Germany) to the film.

[20] At the same time a second, French-made film, by Antoine Vitkine [fr], was released titled The Saviour for Sale: The Story of Salvator Mundi.

[26] Glenn Kenny at the New York Times added the film to his "Critics Pick" list, saying that it "packs the fascination and wallop of an expertly executed fictional thriller".