Hirsch developed slowly as an artist, mounting his first solo exhibition at the age of forty. His adult life, after returning in 1945 from military service in the British army on the Egyptian front, can be divided into three periods: his years living in the Haifa neighborhood of Ir-Ganim, overshadowed by the chimneys of the city's refineries, were marked by hard work as a sign painter and a graphic artist struggling to support his young family. Between 1964 and 1981 he taught at Bezalel; this was Hirsch’s most productive and important period in terms of his artistic growth and expanding social ties. In these years he lived in Jerusalem, where he quickly became an admired teacher and joined the city's vibrant cultural scene. The third chapter of Hirsch's life began after his retirement and ended with his passing in November 1997. During this period, he devoted himself to his art, created his best work, and developed the theory of his drawing method.

In Jerusalem, Hirsch was a familiar and beloved figure in artistic circles, whose members gathered at the Artists House on Shmuel HaNaggid Street, at Café Ta’amon, and at other coffeehouses along Ben Yehuda Street. Tall, slightly stooped, wearing a mismatched tie and jacket and with a mischievous gleam shining through his spectacles, he would respond to those who addressed him as “Mr. Hirsch,” pleasantly correcting them to “von Hirsch.” His sense of humor, particularly at his own expense, was a central characteristic of his interactions with others.

Hirsch’s artistic oeuvre is unique in that it consists entirely of drawings in pen, brush, and diluted ink, in graded shades of grey, from the white of the paper to deep black, on fine paper and in small formats. It recalls the pictoriality of classical European drawing, from Rembrandt to Antoine Watteau and the fantastical drawings of Francisco Goya. The emphasis it places on the quality of line and shape associates his work with the German drawing tradition, from Adolph von Menzel to Max Beckmann, as well as Otto Müller from the Die Brücke group. Like these predecessors, Hirsch’s drawings never served as preparatory sketches for later works, but were finished creations in their own right.

The main subject of Hirsch’s drawings is the human figure, though he also depicted still-lifes, landscapes, and imaginary scenes. The figures he portrayed appear in his works slightly or significantly deformed, in humorous exaggeration to the point of sarcasm, while at the same time rendered with infinite compassion for their physical and psychological frailty. Hirsch’s drawings are immersed in gentle darkness, probably echoing his place of birth, the mining town Beuthen in Upper Silesia (present-day Bytom, Poland), where the air was perpetually suffused with coal dust and dusk reigned even during daytime. Hirsch considered the drawing page as a kind of stage for a dramatic or comedic performance, seeing the images as a score expressing a musical phrase or a short choreographic composition.

In the 1980s, Hirsch gained renown mostly for a large group of drawings of women seated in an armchair in the artist’s studio, passive, languid, gazing into empty space. For him, these women were an inexhaustible source of fascination and learning, as he noted in interviews; he sought to explore their essence and personality, gaining insight into the psychological traits of each sitter. The distortions created under his gaze, at times ironic or even sarcastic, were the result of his effort to understand the inner workings of these women' and to convey something of their life and fate.

Hirsch never sought to copy reality, nor to embellish it. He was drawn to human faults, to unspoken anxieties and to what the body expresses against its owner’s wishes. His work attests to the artist’s unending struggle to discover a deeper truth, understand an obscured reality, and express emotion through movement, gesture, or posture. 

Hirsch’s name became familiar mostly through his years of teaching at Bezalel. His teaching style was charismatic, full of humor, at times somewhat vague. His comments had a variety of sources, including ones relatively unknown at the time, such as the theories of German philosophers Walter Benjamin and Theodor Adorno, alongside English poetry or Jewish texts he had memorized as a child from the prayer book or the Book of Psalms. Despite his own rich cultural background, he treated all of his students with respect, allowing them to feel that “their entire life was still ahead of them.” He insisted on seeing drawing as a fundamental artistic language of prime importance, the Latin of painting. His students, even those who didn’t entirely understand him, felt they were travelling down the right path, a faint light leading their way, and that through perseverance and practice they could reach full understanding. Concepts flew about in the air of his studio, such as division of space, constructive building, proportions between different parts, values, leading the eye, emphasis on the main element, from general to the particular, from the large to the minuscule, the darkest shape next to the lightest. These ideas comprised an entire language that was repeated again and again, until it became a mainstay of his students’ artistic thought.

Notably, Hirsch’s years at Bezalel lent his teaching and work the aura of a resistant minority. The period was one of social turmoil in Israel and at Bezalel, specifically after the 1973 Yom Kippur War; years when conceptual art posed a major ideological challenge and the school underwent processes of academization, including necessary changes in the curricula and teaching staff. A group of activist students, some of whom had been traumatized by the war, raised the flag of change and revolution, organized sit-ins, and demanded greater openness in teaching approaches. 

Hirsch, however, continued to teach drawing according to his own strict method. In fact, he saw his approach as a culturally and professionally revolutionary stance based on staunch historical foundations. The attitude of others to his work was ambivalent: some – students and teachers – considered him a conservative teacher, erroneously calling his work “academic,” and thought that his way of teaching was incompatible with the new winds of change. Many others, including some “revolutionaries,” saw him as a teacher “from whom you can learn something,” who should be listened to. Above all, they appreciated his sense of humor, which contrasted sharply with the utter seriousness of some of Bezalel’s teachers and students at the time. His classes thus offered refuge from the turbulence outside, providing the quiet and concentration needed for serious study.

Following requests by students and other admirers of his work, Hirsch made several attempts to formulate his artistic method in speech and writing. In one of these attempts, he described the development of a drawing, from the first line cast on the sheet, to other lines that join it and relate to each other according to the principle of “absolute asymmetry”, culminating with shapes of different sizes and values that stand in relation to the lines and shapes that preceded them. Later, under the title "Painting from Nature (Whistler's 'Poetry of Sight'): A. Sight, B. Picture Plane, C. Poetry,” he tried to sum up all the elements of his artistic outlook on one page. According to this summary, the drawing surface consists of three parts: “The top part is the space of spirituality, the Heaven, looking down on us; the middle part is Life, where events occur, in which we fight our struggle; the bottom part is the Ground, on which we move and which receives us finally.” The aim of artistic work was what he called “poetry,” that is: “Placement and displacement of the component parts of the visual sentences at or from their expected place in the picture, in order to expose and illuminate a situation of real life." Unsurprisingly, this stage of his doctrine was sometimes viewed as expressing a kind of religious spirituality. Hirsch’s comprehensive method laid the ground for a broad range of interpretation of seen reality, enabling diverse self-expression within the strict confines of drawing from observation. 

All of the above notwithstanding, a large part of Hirsch’s work consists of “drawings from imagination” or “night images.” While for many years he tended to downplay the value of “made-up works,” once they became a significant part of his oeuvre, he described them as “drawings from memory.” This group of works depicts skeletal, human-like creatures in a wood or in barren nocturnal landscapes. The creatures appear to be in constant motion, in total asymmetry, performing a kind of danse macabre or locked in eternal battle. A nightmarish atmosphere pervades, steeped in anxiety, bitter struggle, and collective memories of crime and horror. Nevertheless, these drawings are constructed based on a nearly mathematical sequence, their production consistent and logical, methodical and calculated. The sheet is a kind of musical score; the creatures moving on it seem to create inaudible music or distant sounds and rhythms. These works led some critics to associate Hirsch’s work with the primeval festivals of the Night of Walpurgis in Northern Europe, or, on the contrary, with the musical works of Johann Sebastian Bach, which conform to mathematical principles.

Hirsch’s work was not ahead of its time, nor did it establish a new school, despite his many students at Bezalel and the mature artists that he continued to teach in his private studio after retiring. 

His oeuvre is a world onto itself, secluded in a rich inner realm; poetic and lyrical, at times ironic, it remains outside time and place. Its subjects are humankind – its faults and weaknesses. Using minimal means, it illuminates man’s pathetic attempt to forge connections with others and his forlorn efforts to understand his own fate.