Plinio Colombi studied at the Technikum in Winterthur, where he quickly moved to the department of applied arts. After a stay in Paris, he worked as a decorative painter in Bern and, from 1897, exclusively as a freelance artist. Colombi lived and worked in the most diverse places, including Paris, Bern, Belgium, Jaunpass, Peccia in the Maggia Valley, Kirchdorf near Wichtrach and finally Spiez, where the artist died more late.

Colombi mainly devoted himself to painting landscapes, whose motifs are inspired by the Engadine, the Bernese Oberland, the Lötschental, Simmental and Diemtigtal. After moving to Spiez, he devoted himself primarily to the landscapes of Lake Thun. At the same time, still lifes, and in particular the still lifes with thistle, were at the heart of his work, which always betrays the artist's predilection for the graphic arts.

Plinio Colombi is considered, along with Emil Cardinaux, as a pioneer of poster art in Switzerland.