“I would like to express my gratitude to this town that gave me so much: in Pietrasanta I found my midnight sun”
Knut Steen


He began devoting himself to sculpture around the mid-1940s as an autodidact and then decided to attend the Norwegian National Academy of Fine Arts under the guidance of professors Per Palle Storm and Stinius Fredriksen. In 1948 he created his first important public work: the monument to Friedrich Paasche, placed in the Oslo University park. In 1960, after the erection of the ‘Whaling Monument’, he was acknowledged as one of the major Norwegian sculptors. 

In 1967, he organised his first solo exhibition at the Oslo Artists' Association, which was followed by many others, including: Artists' Association, Oslo 1974, 1984; Bergen 1969; Den frie utstilling, Copenhagen 1973; Kunstnernes Hus, Oslo 1978; Kunstnerforbundet, Oslo 1981; Arco, Madrid 1983; Villa Faraldi, Italy 1985; Leinster Fine Art, London 1983, 1985; Galleri Kampen, Oslo 1983, 1987; Colonnata'L Group, Galleria Santerasmo, Milan 1989; Hadeland Glassverk, Jevnaker 1993; Galleri Roenland, Jevnaker 1991, 1998, 2006; Taiwan 1999; Kunstnerforbundet, Oslo 1967, 1974, 1981, 1984, 1993, 2004; Galleri Cascata 2006; Nils Aas Kunstverksted, Inderøy 2007; Skjerjehamn 2007; Stavern verk 2008; Solstrand, Bergen 2008; Kunstforening, Bærum 2008; Haugar Museum (retrospective, 2009).

He received many commissions, including: "Monument over falne", Kampen Skole, Oslo 1947; "Rudolf Nilsen", Oslo 1953; "To venninner", Nissen Skole, Oslo 1955; "Hvalfangermonumentet", Sandefjord 1960; "Lærerinne og elever", Kampen Skole, Oslo 1963; "Pan", Gjøvik 1966; "Nike", Sjømannskolen,Tromsø 1967; "Moose", in exposed aggregate, ammerud, and wall decoration 1968; Elg, Ammerud Skole, Oslo 1968; "Trojansk hest", Veterinærhøgskolen, Oslo 1969; "Alfred Andersen", Larvik 1973; liten fontene "Alfred", Andersens mek. Verksted, Larvik 1974; "Okeanos døtre", Rådhuset, Oslo (bronze, 1975); relief "Havets metamorfoser", Framhaldsskolen, Nøtterøy 1978; torso "Jens Bjørneboe", Stenersenmuseet, Oslo 1978; "Oppgangssaga", Hønefoss 1979; "Monument Colin Archer", Larvik 1980; "Aurora og Sapfo", Oslo Konserthus 1981; "Aurora", Regjeringsbygget, Oslo 1982; fountain "Fantastico", Rica Hotel, Sanvika 1985; fountain "Mjøsdronningen", Gjøvik 1986; "Metamorfose", Embassy of Norway in Washington, D.C. 1987; "fountain", Norsk Hydro 1987–1988; Park Hotel, Sandefjord 1988; "Hexacord", Musikkhøgskolen , Oslo (989; "La Fortuna", Kosmos, Sandefjord 1989; "Madonna", Våpenhuset, Kampen Kirke, Oslo 1990; "Monument Shetlands-Larsen", Bergen 1995; "Monument Olav Kyrre", Bergen 1998; "Monument Re Olav V, Skjerjehamn" 2007.

Some of his pieces can be found in several private and public collections, among which in Norway: Midtåsen Museum, Sandefjord; Nasjonalgalleriet, Oslo; Riksgalleriet, Oslo; Billedgalleri, Bergen; Kunstgalleri, Trondhjem; Stenersenmusset. Some others are located in public places in Norway and in the Norwegian Embassy in Washington. He also made some illustrations, among which: The ‘Decameron’ by Boccaccio 1990; ‘Kjærlighet’ by Harald Sverdup (1971 and 2006); ‘Som en klovn ser det’ by Heinrich Bőll 1972; and a number of book covers. 
In 2007 he received the ‘Star of Italian Solidarity’ and in 2008 the ‘Medal’ of the Royal Norwegian Order of Sant’Olav. A museum dedicated to him opened in Southern Norway;  it is located in the woods of Jahres Foundation park, near the city of Standfjord. He wrote an autobiography entitled ‘From Garbage to Marble’, since his first job was to drive a wagon for the Oslo Public Cleansing Department, but as soon as he was free he started sculpting and drawing.

In 1973 he arrived in Carrara and since then he lived and worked between Isola di Ortonovo, Liguria, Pietrasanta and Oslo. He created some of his works in the Mino Bruschi laboratory in Carrara and in Studio Sem and Lapis  laboratories and Mariani and Da Prato foundries in Pietrasanta. In the Apuan-Versilia area, he participated in many exhibitions, including, at the Centro Culturale "L. Russo" in Pietrasanta: "Il passato e la presenza" 1982, 1983; "Il disegno degli scultori" 1988, 1993; "Premio Internazionale di Scultura 'Gioia Lazzerini'" 1994; "Omaggio a Sem" 1997; Il "Malbacco/L'altra faccia della scultura" 2003; as well as: "Scultura alla Versiliana", Marina di Pietrasanta 1982; Montignoso, Massa (solo exhibition, 1985); "Sculture di Passaggio", Parco di Villa Schiff-Giorgini, Montignoso, Massa-Carrara 1987; Colonnata, Massa-Carrara (solo exhibition 1989); "Scultori a Pietrasanta2, Studio d'Arte La Subbia, Lido di Camaiore 1991; "Trent'anni da Sem", Piazza Duomo, Pietrasanta 1991; "50%: 100 artisti in cantina", Fondazione Arkad, Seravezza 2002. In 2010, he was awarded the "Premio Internazionale 'Pietrasanta e la Versilia nel Mondo'" by the Circolo F.lli Rosselli of Pietrasanta, where he presented a solo exhibition at the Centro Culturale "L. Russo".