The youngest of four children, Holtz was born and spent his early childhood in Skierniewice, Poland, a small town near Warsaw. His father was a hat maker and a furrier. In 1935, prior to World War II, when Holtz was ten years old, his family moved to Jerusalem, Israel, where they settled in the Geula neighborhood near Meah Shearim.
Itzhak Holtz's passion for art began early. When he was five years old, in Poland, his father first drew a picture of a horse and sled in the snow for him. The young Holtz looked at the drawing and studied it in wonderment. From that moment on, Holtz remembers, he constantly begged his father to draw for him. His enthusiasm for art grew and Holtz longed to study art. In 1945, he enrolled at the Bezalel Academy of Art and Design in Jerusalem, where he primarily studied lettering and poster work in a program geared toward commercial art Holtz became interested in painting, prompting him to move to New York City in 1950 to study at the Art Students League of New York under Robert Brackman and Harry Sternberg, and then at the National Academy of Design under Robert Philipp.
Holtz has stated that his artwork, which primarily but not exclusively, depict scenes of Jewish spirituality and tradition, is driven by his Orthodox Jewish beliefs: "You have to live that religious life to fully capture it on canvas." He has been classified in the school of genre painting, often depicting street scenes of ordinary people in everyday Jewish life in the back alleys and markets of Jerusalem neighborhoods such as Me'ah Shearim and Geula; and in New York neighborhoods and hamlets such as Monsey, Boro Park and Williamsburg. Along with street scenes, his work includes portraits of scribes, tailors, cobblers and fishmongers, and images such as shtetls, lighthouses, and wedding scenes. He started out painting mostly portraits in order to support his family, before expanding to include street scenes. His beloved subject matter is painting scenes of Jewish life, his childhood memories when his mother took him along shopping for the Sabbath to the markets of Meah Shearim, has left a deep impression on him and influenced many of his works. Holtz has experimented in the abstract, but then reverted to representational and figurative art to which he devoted himself exclusively. His Israeli street scenes are said to combine “an affectionate recollection of the past with the brilliance of the color of modern Israel.”
Holtz has stated that he struggled at first when he arrived to the USA because of financial reasons and because he only knew Polish, Yiddish and Hebrew, but then made good ties with his instructor who greatly influenced him Robert Philipp who helped him make friends and referred him to paint portraits.
Examples of Holtz's work throughout the years include: Yerusalem Wedding (2010), depicting a Chuppa in Jerusalem on early evening, oil on canvas; The Funeral(1966), depicting five stoic Hasidim carrying a body on a bier over to a gravesite, with the people behind them crying, in charcoal on paper and oil on canvas; Rejoicing (1974), an image of religious men dancing, in felt pen and marker on paper; and the oil painting Shamash Learning in Shul (2003), a portrait of a pious Jew studying the Talmud inside a claustrophobic synagogue scene.
Throughout the years Holtz has created hundreds of works in many art mediums, including, genre scenes, portraits, still lifes and landscape scenery, his works are sought after by art collectors worldwide, and he has been called the greatest living Jewish artist. It is said that no artist ever explored the Jewish subject like Holtz. Today some of his oil paintings have been commanding over $100,000.
Holtz creates his scenes after researching locations, and often uses locals as models. He paints slowly and with great care, but with a swift Impressionistic style. The people in his portraits and scenes are generally more cheerful and optimistic than standard portraits of Hassidic individuals. He paints oils and watercolors, and also does felt pen, pastel, marker, ink and charcoal drawings, as well as woodcuts. His oil paintings typically have a brown hue, while his work with felt pen is often in sepia tones, and on some of his works he used very bright colors, with a strong emphasis on the interplay of light and shadow. He is heavily influenced by the ancient staircases and alleyways of Jerusalem, with its modest religious population, which has made a strong impression on him in his youth, the streets of Tzfat, and the works of Rembrandt, Johannes Vermeer and Peter Bruegel, as well as Jewish artists Moritz Daniel Oppenheim, Leonid Pasternak and Isidor Kaufmann have had a strong influence on him. He has said that realism is the best way he can express himself.