Orphaned at an early age, Zadorozhnyi grew up on the streets of Kyiv until the Friends of Children society took him under its care. To support himself, he worked as a stoker and a courier for the newspaper Visti. Despite the hardship, he devoted himself to drawing. The family that temporarily sheltered him gave him a second name — Valentyn.
Due to health issues, he was unable to enroll in the United School of the Caspian Naval Flotilla in Baku, remaining instead as a librarian there. With the outbreak of World War II, he went to the front, serving in the 68th Marine Rifle Brigade. Twice wounded, he was later assigned to a reserve division in Vologda, and in the final year of the war, transferred near Arkhangelsk to the staff of the White Sea Military District, where he was engaged in artistic and design work. During his service, he was unjustly accused and imprisoned, though acquitted six months later.
His early works included political posters and pieces on revolutionary and historical themes, executed in the traditions of Stalin-era socialist realism. Yet Zadorozhnyi strove to transcend this inherited style, making national-historical themes central in his practice.
By the early 1960s, his art had acquired a distinctive style and a new plastic language. One significant work from this period is My Fellow Countrymen (On the Site of Former Battles), a striking example of the Ukrainian variant of the “severe style,” then particularly popular among young artists. The painting provoked heated debate: Zadorozhnyi was accused of Boychukism, nationalism, and formalism.
Although painting was his passion, he never relied on it as his main livelihood. Among his major commissions of the 1970s–1980s were stained-glass windows for the Kyiv funicular and Kyiv University, as well as the design of the Lybid Hotel, where he created tapestries, carved wooden columns, lamps, tableware, and even uniforms for the restaurant staff.
Zadorozhnyi produced numerous monumental and decorative works, including stained-glass windows, cement reliefs, and mosaic panels. These works reveal his deep fascination with Ukrainian folk song: every line of his compositions seems imbued with lyrical quotations. Such formal innovations later carried into his easel painting, culminating in a unique personal style.
In a radical act of artistic and philosophical choice, Zadorozhnyi destroyed part of his own body of work. Many of his surviving paintings date to the final year of his life, as if he were racing to bring all of his ideas to completion.