Robert Buhler was born in London in 1916. Both his parents were Swiss. In 1933 he studied at the Kunstgewerbe Schule in Zurich and later in Basle. He then went on to St.Martin's School of Art where he was taught by Vivian Pitchforth, Leon Underwood and Harry Morley. He won a Scholarship to the Royal College of Art (RCA) in 1935. Percy Jowett was Principal and Gilbert Spencer Professor of Painting. After six months he gave up his scholarship at the RCA and took a studio in Camden Town, as well as doing some part-time teaching at Wimbledon Art School. As well as painting in London he rented various cottages in East Anglia.

Although Robert Buhler was not part of the Euston Road School, founded by Graham Bell and William Coldstream, he often met those who were involved, including Victor Pasmore and Rodrigo Moynihan. Buhler's approach to painting, with its restrained use of colour and disciplined handling of paint was in keeping with the tenor of Euston Road.

On leaving art school he received a commission from Shell, and began exhibiting in 1936, when his work was singled out by the art critic Herbert Read. His superb portrait of Stephen Spender in 1938 caught the eye of the critics and was bought by The Contemporary Art Society. He exhibited at the Leger Galleries in 1942 with Vivian Pitchforth. He had also begun to exhibit at the Leicester Galleries in their group exhibitions such as "Artists of Fame and Promise". After the war, Buhler taught at the Chelsea School of Art under Harold Williamson. Also teaching there were Henry Moore, (Elizabeth Frink was a student) and Graham Sutherland.

Buhler is best known for his landscape and for his portraits. He painted a wide range of well-known people including Sir John Betjeman, W H Auden, Francis Bacon and Ruskin Spear.

Sir John Rothenstein described Buhler's approach to portrait painting in an article: "He paints directly from the subject, requiring six, eight or occasionally ten sittings of thirty minutes to two hours and works afterwards, especially on the setting, furniture, windows and the like. The subject is accurately "placed" by drawing and built up by colour relationships. Oil is his preferred medium, and he also uses pastel". In the same article Rothenstein wrote "Buhler's landscapes appear, at least at first glance as straightforward representations, which is far from the fact, ...their realistic look is illusory, for they are based upon elaborate geometrical designs and their apparent straightforwardness is testimony to the thought devoted to their composition".