The pictorial realism of the young Van Lint demonstrates readily bold formal and chromatic simplifications, inherited both from Ensor and from the Brabantine Fauvists. Like them, and benefiting from an innate sense of expression through color, the young painter becomes part of this pictorial renewal manifested also by artists such as Gaston Bertrand and Anne Bonnet, who joined him at the Academy of Saint-Josse. Already labeled in 1938 as Young Art (Art Jeune) in the Brussels Gallery Atrium, the aesthetic affinities are reinforced between these artists, which leads, following their exclusion from the Spring Salon (Salon de Mai), to group with some young fellow students of the Academy under the name of The Free Way (La Route Libre), and organize in 1940 an exhibition at the Toison d'Or Gallery in Brussels.

 Once the war ended with its deprivation of liberty and the academic aesthetics promoted by the occupier, the time has come for Van Lint to continue exploring a new visual language, which as in the example of elders as Ensor and Brusselmans, could bring definitive emancipation from the realistic view, a language in which a particular object of reality becomes an excuse to a more abstract recomposition  - which will be called - "derealizing", by his first biographer, a language capable of expressing a new consciousness of life, both more anxious and subjective. In May 1945, Van Lint finds encouragement in this new artistic quest when he discovered the exhibition The Young French Painters (La Jeune Peinture Française) at the Palace of Fine Arts in Brussels. A month earlier, he had the second individual exhibition. Innovative events are accumulating in the immediate aftermath of the Liberation; on July 3, the association The Young Belgian Painters (La Jeune Peinture Belge) is launched at the initiative of Robert Delevoy and presided by René Lust, a lawyer. This association brings together twelve Belgian artists, the stars being undoubtedly Van Lint, Bertrand, Mendelson, and Cox. Some other thirty artists will join them afterwards. Louis Van Lint is chosen to represent his colleagues on the Board of Directors. The patrons who support The Young Belgian Painters acquired several works signed by the artist, shown at numerous exhibitions under his aegis: in Ostend, Paris (Galerie de France), the Hague, Amsterdam, and soon in Buenos Aires, Stockholm, Cairo, Zurich, Bordeaux, Brussels, finally in Oxford, Venice, Mons, Antwerp, Rome.

At each of these exhibitions, Van Lint distinguishes from his colleagues by the audacity of its pure and contrasting colors: “A magician of the palette with a vividness that individuates him", notes the Parisian art critic Gaston Diehl talking about The cabins (Les cabines ou les tentes), a canvas soon acquired by the Museum of Ghent. The artist focuses then on a new way to transpose reality (a cabbage, a basket, figurines and dolls, boats, a lamp, a musical instrument, a lattice, a face, an attitude), making use of both candid and contrasting chromatic harmonies, and a simplified design that cultivates the arabesque of the line and monumentalizes the color schemes. In this regard, a canvas as Still Life. Glass  lamp  (Nature morte. Verre à lampe), first acquisition of the Royal Museums of Fine Arts in Brussels) is one of the milestones of this evolution, as it foreshadows the artist’s imminent entry into abstraction.

In 1941, the Youth Art (Art Jeune) exhibition at the Atrium Gallery in Brussels highlights Louis Van Lint, who won with this occasion a Prize awarded by the newspaper Le Soir. The same year, in the difficult context of the occupation, Louis Van Lint, Gaston Bertrand and Anne Bonnet succeed to set up an exhibition of young Belgian artists at the Fine Arts Palace in Brussels, called Contribution 41 (Apport 41). The following year, Louis Van Lint participates alone (his first personal exhibition), while Robert Delevoy, who opened his Apollo Gallery, takes over and organizes the version of 42 of the exhibition Contribution (Apport). Because of the intimist works painted by Van Lint up until that time (interiors, portraits, urban views), the art historian Paul Haesaerts mentions him in a book grouping a series of Belgian artists born at the beginning of the century, that he names The Animism. Back to human. In 1943, however, some new works by the artist demonstrate a spirit well opposed to this Animism. There was a clap of thunder, in effect, during the art show Contribution 43 (Apport 43) when Van Lint exposes The Flayed Body (L'Ecorché), a canvas with acid tones and a style showing a human figure exhibiting without modesty nerves and viscera, and which he subtitled, as an anti-animist pamphlet, Back to Human (Retour à l'humain). This major work is part of the Thomas Neyrinck collection, administered by the King Baudouin Foundation.

A feverish atmosphere and a sense of revolt are displayed by a few other works of this year, as The Self-portrait with a Red Tie (Autoportrait au col ouvert ou à la cravatte rouge), The Millenary Polar Star (La Tramontane Millénaire), or The Law : the scales of justice are flawed (Le Droit se balance ou la Justice bafouée), a painting of a quasi boschian verve in which one can see in a theatrical courthouse a series of judges and lawyers forced to the gallows among sculpted allegories covered by ensorien masks. 1943 is also the year when the artist wins  in Brussels the Popular Art Prize (Prix de l'Art Populaire). His work raises interest among critics and his first art collectors.

In 1948, Louis Van Lint is the first Belgian painter of his generation to create abstract works having a lyrical character (shortly before, Jo Delahaut had approached the geometric abstraction). Already, a work as Composition - Interior (Composition - Intérieur) hardly allows to perceive, under the ingenious partitioning of multicolored flat tints, a furnished interior. Various other objects then become also a pretext of eloquent formal arrangements where the elegant arabesque and the dialogue of contrasting colors prevail. However, starting this year, 48, it is principally the nature, a nature seen in the force of its primordial elements and perceived through the subjectivity of the artist, which will now lead the artist to some of the most inspired abstractions. In this regard, Heaven, sea and earth (Ciel, mer et terre), a canvas with merging waves and clouds, is the first significant step in the direction of this lyrical abstraction which will be the mark of the reputation and originality of Van Lint's art.

The artist ventures afterwards in a spontaneous style using the emergence of mobile and expansive signs, which appear as formal metaphors of the vegetal, organic, or cosmic nature (Music in hell, Musique en enfer). These signs, these kinds of elongated cells with curves closely intertwined but readily broken by angles, find their consistency and power of expression within the creative use of Fauves flat tints  Symphony in Red (Symphonie en rouge), sometimes also in darker and monochrome tones Magical Composition (Composition magique). In 1950, such works are shown at the Palace of Fine Arts in Brussels, then in a Parisian Gallery and in Amsterdam in 1951. During these years, Van Lint is admired by his trainees of the COBRA group, also invited to participate in some of their exhibitions and activities. In 1949, he notably created his Magic Lantern (Lanterne magique), a stunning work, made of cut cardboard and cellophane, rotating (the first kinetic work in Belgium), projecting abstract forms. "Older and separated from the Danish influence, Van Lint is quite close to us and inspires us”, wrote the poet OJ Noiret from CoBrA. As early as 1951, the year when the Ministry of Culture asks the art critic Léon-Louis Sosset to write a first monograph consecrated to the artist, some paintings indicate the artist's desire to establish his reinvention of the real through serial compositions or insistent orthogonal, vertical, horizontal and oblique segments punctuating the canvas or gouache. There are also some works inspired by the stained glass windows of Chartres in the Royal Museum of Fine Arts in Antwerp, sometimes by an urban scaffolding, or, as in the wonderful Musical Composition (Composition musicale), by musical instruments. Shown in various international exhibitions, the works of this time bring to Van Lint a few prizes: in Santa Margherita-Liguria in 1950, in Lugano in 1952, and cause him to be sent by Belgium to the first International Biennial of Sao Paulo in 1951. This foundation within the abstract, does not stop Van Lint to create also figurative works, marked  clearly by his fondness for abstract arrangements of shapes and colors Man Shaving, Self-portrait (Homme se rasant, autoportrait).