When Ken Thomson, the 2nd Lord Thomson of Fleet, owned The Times, the first column that he turned to in the morning was the saleroom report. He was a passionate and highly knowledgeable collector of paintings and works of art, and now, 2½ years after his death, his collections are housed in the Art Gallery of Ontario (AGO), in Toronto, strikingly transformed by Frank Gehry. It is hoped that the building, which was opened officially last November, will prove to be as great a draw as the architect’s famous Guggenheim Museum in Bilbao.

Although Gehry, like the Thomson family, hails from Toronto, this is his first building in Canada. It is particularly appropriate, since his grandmother lived just across the park from the old Art Museum of Toronto, and he attributes his youthful artistic awakening to visiting it. A 1990s Post-Modernist wing has been demolished, but the best 1920s galleries have been retained within Gehry’s new work, as has the room designed by Henry Moore for the display of his casts.

Externally the most striking features are the curved glass and Douglas fir sculpture gallery running the length of the northern façade, and the gunmetal-blue tower housing contemporary art. “Tears” at either end give the dramatic gallery the look of a giant salmon swimming above Dundas Street, with a lower fringe to prevent ice from falling into the street at the end of Toronto’s fierce winters.

The main entrance has been repositioned to carry visitors directly into the art without interruption. The intention is to draw people in to experience the building, and thus come to the contents. As the director and chief executive officer Matthew Teitelbaum says, through Gehry’s remarkable design the new AGO declares itself “an open invitation to enter and participate in something memorable and exciting”.

Elements of the interior include a swirling sculptural staircase rising from Walker Court, the heart of the old building, now given a Florentine feel, and angled skylights which give an even, deflected light. Gehry has said that he seeks to create “tension between institutional scale and domestic intimacy”, and he succeeds admirably, combining grand, ambitious gestures with meticulous attention to detail. An example of the latter — flying in the face of museum orthodoxy — is an elbow-height wooden rail, Douglas fir naturally, just inches from a hang of oil sketches, so that one can lean right into them.

As Thomson wished, his collections are displayed together, but where they complement the gallery’s other holdings the relevant displays can be accessed one from the other. This is most relevant in the hangs of Canadian art, from Cornelius Krieghoff and Paul Kane in the 19th century to Lawren Harris (1885-1970) and the Group of Seven, and in particular Tom Thomson (1877-1917) to David Milne (1882-1953). These displays will undoubtedly dispel any dismissive perceptions of Canadian painting that may be held by elsewhere.

A principal element of the Thomson Collection consists of European works of art, including medieval ivories, wood carvings, metalwork, ceramics and miniatures; also Egyptian amulets and Chinese snuff bottles. The ivories are a particular delight, running from 13th-century diptychs, knife handles and combs, to busts and reliefs by the 18th-century Huguenot David Le Marchant and 19th-century busts after Chantrey by Cheverton. A collection of memento mori has its own display chamber, as does a treasury, or Wunderkammer. The Baroque items lead on to Thomson’s greatest European painting, The Massacre of the Innocents by Rubens. For the opening it is hung with loans including Rubens’s Samson and Delilah from the National Gallery, London, and The Entombment from the National Gallery of Canada.

At a lower level (which can be glimpsed enticingly from above) is a gallery celebrating another of Thomson’s passions: model ships. There are 17th and 18th-century Navy Board dockyard models, prisoner-of-war carvings and 20th-century models that show all the intricacy and skill of their predecessors. Here Gehry’s mastery of lighting and the detail of case construction and display are at their most impressive. Two very large, sinuous cases containing flights of models follow Hogarth’s “line of beauty”, and, remarkably, no two of the many sheets of glass of which they are constructed are quite the same size or shape.