His father, Carlos Sotomayor Cáceres was a Civil Engineer who worked for the Chilean Railway Company (Empresa de los Ferrocarriles del Estado), married to Julia Román Morales.
In his teenage years, Carlos Sotomayor met the painter and sculptor Laura Rodig, who had just come back from Europe, and worked with her, putting up an exhibition together with Pedro Olmos.
In 1934 Sotomayor joined the Grupo Decembrista, together with María Valencia, Gabriela Rivanedeira, Jaime Dvar and Waldo Parraguez.
Two years later, Carlos Sotomayor married Franka Serka Jurac, fellow student at the Fine Arts College.
Sotomayor exhibited his works at the Exposicion de Pintura Chilena Nueva in March 1962, organised and sponsored by Empresa Esso Oil Co. Nemesio Antúnez and José Balmes also participated.
An excellent draughtsman, with a line capable of expressing both the graceful and the vigorous in the classical tradition, Carlos Sotomayor could have worked entirely figuratively, an approach which would have brought him instant commercial success.
As a result, in 1934 he joined the Grupo Decembrista, a neocubist group led by the poet Vicente Huidobro, one of his most fervent admirers, who revealed his enthusiasm for Sotomayor's work in the magazine PRO published in the same year.
E. Anguita, who won the 1988 Writer of the Year Award, Julio Molina and Guillermo Atías were among his greatest apologists, praising him as a painter who did not confine his work to the replication of reality, or to conventional romanticism.
Supported by the solid foundation of his drawings, Sotomayor alters reality in order to render it more real, in the quest for more sensitive communication through highly personal, expressive forms.
Sensitive to current events, the initial figuration suddenly emerges in his work, but not as a final phase of his expression, only as the rebelliousness of a pure spirit.