Josef Kos first studied in the years 1948–1952 at the Higher School of Applied Arts in Prague under professors Petr Dillinger and Antonín Pospíšil. He continued his studies in the years 1952–1958 at the Academy of Arts, Architecture and Design in Prague, in the studio of applied graphics and book illustrations with Professor Karel Svolinský. After completing his university studies, Josef Kos started working in Prague as an industrial artist and designer of neon advertisements. In 1961, he returned to his native Vysočina and settled permanently in Jihlava. Here he first worked for a short time in the Vysočina Regional Gallery as a worker for traveling exhibitions and then became an assistant professor at the Department of Art Education at the Jihlava Pedagogical Institute. After its abolition in 1965, he chose the path of a "freelance" artist and devoted himself to applied work, especially graphic editing of books and catalogs, designs for posters, invitations, commemorative sheets, diplomas, medals and badges. He also designed, for example, match stickers, but also mosaics and stained glass windows (the well-known stained glass window with the motif of colliers in the lounge of the Zlatá hvězda hotel in Jihlava from 1986).
Initially, he continued his studies and devoted himself mainly to graphics, mainly woodcuts and linocuts. In his free work, he gradually abandoned these graphic techniques in favor of color lithography, which allowed him a painterly approach to work. The mastery of lithographic chalks led him to separate pastels, and from them it was only a step to oil paintings, which allowed him to work in larger formats. The first painting painted in oil dates back to 1953, when the realistically conceived oil painting Ferry in Troja was created, otherwise he used this painting technique rather sporadically and only occasionally. He mostly painted pictures at the request of his acquaintances and friends. Basically, he didn't get into oil painting until decades later, in the early 1980s.
This period can also include the painting from the OGV collections "Spring evening", probably from 1982, which is a characteristic example of his work, whose main source of inspiration was the landscape of the Bohemian-Moravian Highlands captured in all seasons. He unrepeatably captured picturesque village or forest nooks, cottages on the hillside, fields and meadows with draws, flooded quarries, blind branches of rivers, pools and swamps, but he also created a cycle of urban sceneries from Jihlavsko, Třebíčsko, Žďársko, Pelhřimovsko and Havlíčkobrodsko.
In landscape painting, Josef Kos does not try to faithfully capture reality, but created his own pictorial language based on poetic characters, into which he transformed his childhood memories and the emotional characteristics of lyrical landscape scenes, often shrouded in a kind of dreamy haze.
Josef Kos was a member of the SČVU (Union of Czech Visual Artists) and in the years 1990–1996 the Association of Visual Artists of the Highlands (Union of Visual Artists of the Czech Republic). He was also ranked among the important citizens of the city, in 2009 he received the Award of the City of Jihlava for his lifelong contribution to the visibility of Jihlava and Vysočina through an artistic work.