NAM JUNE PAIK was apparently the first anywhere in the world to be labelled “video artist”. But as so often happens with forerunners, his definition as a video artist was by no means what the world eventually decided the term should mean. For all practical purposes, he was, rather, a sculptor and performance artist who used television sets and video machines as his raw material. Of course the screens were generally showing something, as often as not devised by him, but it was never the be-all and end-all of his art.

Paik came towards what was to be the core of his life’s work by indirection. Born in Korea, he began his academic career by studying music, first in Korea, then at Tokyo University, where he wrote his thesis on Schoenberg, fascinated as he was by the mathematical side of the composer’s later works in the twelve-tone system.

This combination of scientific precision and hard-won artistic freedom was to characterise Paik’s own mature work. In 1956, when he turned 24, he travelled to Europe and settled in West Germany, still following his interest in advanced music, and in 1958, while attending the Summer Course for New Music in Darmstadt, he met two people who were to prove deeply influential on his own art, the avant-garde composer John Cage and George Makiunas, founder of the “post-surrealist” art movement Fluxus.

Both men were interested in the possibilities of artistic performance, as well as the application of mathematics and modern philosophy to the visual arts. It was Paik’s notion to apply all this to the then despised medium of television.

His first solo exhibition, Exposition of Music: Electronic Television, in Wupperthal in 1963, was to be recognised as a turning point in the history of 20th-century art. Paik used dozens of television monitors, scattered higgledy-piggledy around the gallery, some lying sideways or upside-down, all modified so as to distort what was being shown (mostly current television transmissions) and thereby change the spectator’s attitude towards it from passive receptivity to active mental involvement.

The following year Paik made the decisive move to New York, where he taught and continued to pour out work in sometimes dizzying profusion. Virtually single-handed, he transformed artists’ attitudes towards television and video, showing all sorts of ways that they could become a flexible medium for art. Paik himself expanded his practice in various directions, taking in not only his trademark installations with manipulated television screens, but also elements of performance and the shooting of elaborate video pieces, often in collaboration with such friends and associates as Cage, David Bowie, Merce Cunningham, Laurie Anderson and Joseph Beuys, as well as Charlotte Moorman, his most regular collaborator in his early performance pieces.

The performance side of his work came mainly from the associations with the Fluxus movement, while music continued to play an important part in his art right up to his death. Not necessarily music as we have known it: Cage’s revolutionary theories about the role of random noise and total silence (supposing such a thing could ever exist) in musical performance had a lasting effect on Paik.

He continued throughout the Seventies and Eighties to put together elaborate installations, combining what was then recognised as video art with quasi-sculptural constructions of television screens, sometimes teasingly equated with such exotics as tropical fish in Video Fish (1975) or hothouse plants in TV Garden (1982). There was always a strong element of humour, and a delight in leading spectators on false or delusory tracks, which meant that those who went to demand “but is it art?” or protest at the obscurity of this modern stuff would come away charmed and entertained.

Paik’s career climaxed with a major retrospective, The Worlds of Nam June Paik, at the Guggenheim Museum, New York, which commandeered the whole spectacular space for classic works and pieces specially created for the museum’s towering circular atrium, including the play of coloured lights and a seven-storey “waterfall”.

Paik suffered a major stroke in 1996, which left him partially paralysed, but though his own performances were curtailed, he continued to produce new work at an astonishing rate, masterminding it all from his Miami apartment when he was unable to travel. He remained one of the very few artists who single-handedly changed the course and tone of art in the 20th century.

Nam June Paik, artist, was born on June 20, 1932. He died on January 29, 2006, aged 73.