Sumbat was born on October 19, 1913, in New Julfa, the Armenian quarter of Isfahan, the old capital of Iran and the center of Iranian arts and crafts. His father, Hovhannes, was an auctioneer of specialty items and a watch repairman. He died in 1915 when Sumbat was barely two years old. Sumbat was raised by his mother, Tagouhi, who is said to have had artistic talents. 
Sumbat's grand father, named Kiuregh, was the priest of Sourb Hovhanou Church in New Julfa. In accordance with the Armenian tradition, the family took his priesthood name as their last name - Der Kiureghian. The "Der" part signifies lineage from a priest.
Indications of Sumbat's interest and love for painting appeared early in his childhood. In her memoir, Sumbat's older sister Sirik recalled one teacher saying "Sumbat's assignment notebook is filled with so many beautiful drawings that I hate to make corrections to his many mistakes." Sirik also recalled Sumbat at the age of 7 or 8 drawing landscapes, people and animals during family vacations in Armenian villages near Isfahan. In a contest organized by his school in 1924, Sumbat exhibited these paintings and won the first prize.
Sumbat's early teachers were local artists Yeghia Yegijanian and Hagop Vardanian. The most decisive event in Sumbat's career occurred in 1929, when renowned French-Armenian artist Sarkis Kachadourian arrived in Isfahan to paint from the frescos in Ali-Ghapou and Chehelsotune palaces. Educated at the Academy of Art of Rome and Ecole des Beaux Arts in Paris, Kachadourian was a learned and worldly man with broad cultural interests and a vast knowledge of Western and Eastern art. 
He was also an activist and an organizer. Arriving in Isfahan in the fall of 1929, Kachadourian quickly made contacts with the Armenian community of New Julfa and set up an art class. More than 25 young men and women enrolled, among them Sumbat and his younger brother, Johnny. Kachadourian noted Sumbat's innate talents and recruited him as an apprentice to help him with his work in the two palaces. The experience had a tremendous influence on Sumbat. He was awed by Kachadourian's mastery of brushwork and bold strokes. He was also impressed by his reverence for his subjects. Sumbat started by carrying paint cans and canvases, but soon was doing preliminary sketches and paintings for his master. In conversations with Kachadourian, Sumbat learned about great Western artists and about Indian, Japanese and African art. More importantly, he came to realize how valuable the artistic traditions in his own hometown were. Encouraged by Kachadourian, at the age of 17, Sumbat decided to become a professional artist.
Soon after Kachadourian's departure from Isfahan in 1930, at the age of 17, Sumbat opened his first studio-gallery, which he called Negarestan-eh Sumbat, Sumbat's Art Studio. Initially, he worked on handicraft and designed carpets in addition to painting. However, soon it became clear that his watercolor and gouache paintings were immensely popular and he could make a living by doing art alone.
Isfahan and its environs are rich in subjects that Sumbat liked to paint. The landscape is mountainous and dry, full of earthy colors under a blue sky. The woods along Zayandeh river are bright green and provide a sharp contrast with the burnt umber of the nearby rocky hills and the cool blue and purple of the distant mountains. Sumbat never liked forests. They were "too green" for him. He liked open landscapes with warm earthy colors. The many historical sites around Isfahan also provided ample inspiration for him: The Madraseh Chaharbagh seminary, the Shah Mosque; the centuries-old Sio-se-pol, Khajoo, Marnoon and Shahrestan bridges, pilgrimage sites in the vicinity of the city, the bazaar, caravansaries, and pigeon towers.
There are two regions around Isfahan, which, starting in the sixteenth century, have been populated by picturesque Armenian villages. One is the region of Fereydan (Peria in Armenian) and the other is Charmahal. As a child, Sumbat had visited these villages with his family on summer vacations. Now he found them to be a major source of inspiration for his work. The sight of peasants working in the field, a shepherd returning the flock in the evening sun, women making the Armenian lavash bread in the tunir (ground ovens) or washing carpets in the river, a wedding procession with musicians playing the zorna and dohol, and women in folk costumes filling water jugs at the village spring inspired him. His renditions of these pastoral scenes are not only a celebration of idyllic life, but also preservation of traditions and images that were soon lost to modernization.
Sumbat had an innate understanding of nature. He saw and recorded the texture in the bark of a tree, the cool temperature of the water flowing in a stream, and the difference in the color of a leaf in the spring, summer and fall. As E. Nazari-Noori has said, "He is intimate with the Iranian soil and sun. He knows the secret of seasons. He is a narrator of Iranian history and a storyteller of the life of simple people."
Throughout his life, Sumbat preferred exhibiting his paintings in his own studio. He disliked middlemen and never worked with art dealers or managers. Neither was he keen on participating in exhibitions and contests. He preferred to meet with his patrons in his own studio, serve them his sweet coffee, and personally negotiate the sale of paintings. Nevertheless, he participated in a large number of one-man and group exhibitions, particularly during his stay in the United States.
In 1944, Sumbat married Arax Aftandilian, also of New Julfa, after courting her for several years. They had three children: daughter Siroush born in 1945, son Armen born in 1947, and daughter Tagoush born in 1959. A pictorial history of Sumbat's family can be seen in the Christmas cards that he created with the family members acting various ethnic roles.
Sumbat's first formal exhibition was in April 1944 at the Anglo-Persian Institute in Isfahan. He was among sixteen Isfahani painters, including renowned miniaturist Mosavver-ul-Mulk and fellow New Julfa artist Yervand Nahapetian. In the introduction to the catalog of the exhibition, Jan Ellison wrote:
In Isfahan, where children, at an age when in Europe they would be - with difficulty - making mud pies, become expert engravers and bracelet miniaturists; where the merest fruit vendor constructs ornamental pyramids of the most intricate pattern and design; where every other shop in the Chaharbagh or in the bazaar is a workshop in the Italian Renaissance sense, containing artists in silver, in ivory, in wood, in clay, in wool ... in such a place where art is not the monopoly of a few worried specialists but the natural spontaneous expression of a traditionally creative people, it has only been possible to exhibit one out of the many branches of Isfahani art. This time it is painting.
Sumbat exhibited two oil paintings of Persepolis and four watercolors of scenes from Isfahan and Shiraz. The next exhibition was in February 1948 in Abadan, sponsored by the Anglo-Iranian Oil Company. The exhibition was an extraordinary success. Virtually all exhibited paintings were sold and Sumbat received many commissions. He was widely praised for his work: "Splendid choice of colors," "Surprisingly high standards" and "Sumbat Kiureghian is an artist of whom nature, his sole teacher, can be proud." Stanley F. Foster, the author of the last quotation, was to have a profound influence on Sumbat's career.
A consulting engineer and an accomplished amateur artist on his own right, Stanley Foster offered to fund a six-month journey through the Middle East and Europe to England, if Sumbat would agree to teach him on the way. And it was so that on June 18, 1949 Sumbat and Stanley began a journey from Abadan and traveled through Iraq and Syria to Lebanon, from where they took a boat to arrive in Naples, Italy, on July 3. They then went on to Rome, Florence, Venice and Paris, and arrived in London on August 13. Along the way, they visited museums and historical sites and made numerous sketches and paintings. Sumbat was finally able to see the works of great impressionists Monet, Degas and Pissaro, postimpressionists Cezanne, Toulouse-Lautrec and Van Gogh, and renowned British watercolorist Turner who remained his favorites all his life.
Sumbat and Stanley enrolled in the Anglo-French Art Center in London, where Sumbat received formal training for the first time in his life. They visited art galleries, museums and artists in London. On one occasion they visited Sir W. Russell Flint, the renowned British watercolorist. Upon seeing Sumbat's watercolors, Flint declared him "brother in brush."
Before his return to Isfahan in February 1950, Sumbat held an exhibition of his watercolors from his travels in Europe and England at the Art Center. 
A number of the paintings were sold, providing funds for his return home. Stanley Foster remained a close friend and admirer of Sumbat until his death on August 30, 1965. In 1962 he added a studio-gallery to his country home at Hurley near Maidenhead in England and called it "Sumbat Studio." In one of his many letters to Sumbat, he wrote:
Here it is spring and all the world is green. My new Sumbat Studio and picture gallery is finished and I have a hundred pictures hanging, -- oil paintings, watercolours, & pastels. Many people come to see them and keep me busy. I have done many portraits and have more to do. All the time I am grateful to you Sumbat for our journey because then I learnt so much. Your portrait hangs in the middle of the gallery and I tell everyone about you.
After returning from Europe, Sumbat resumed his artistic work with renewed vigor. He experimented with new techniques and styles. In one experiment, he used his newspaper palette as his canvas. With a few brush strokes, the random mix of gouache colors and printed letters came alive, suggesting a crowd in a traditional Iranian bazaar. In time, this technique, popularly known as "Sumbatism," became one of Sumbat's signature styles.
By early 1960's, Sumbat had become a renowned artist in Iran and an undisputed master of the watercolor medium. His studio had become an institution in Isfahan and a popular destination for art-loving visitors and tourists. The people of Isfahan revered him as their artist. Mail simply addressed to "Sumbat, Isfahan" would be delivered.
In 1965 Sumbat was invited by ARAMCO to Saudi Arabia to exhibit his paintings and teach art in Ras Tanura and Dhahran. The Saudi landscape and culture further enriched his experience, an effect that is evident in some of his later paintings. Further exhibitions were held in 1971 in Tehran and in 1976 in Los Angeles, during his first visit to the United States. A major retrospective of Sumbat's works along with those of three other Iranian watercolorists was held in Teheran in 1978.
Sumbat and his wife, Arax, moved to the United States in 1980 to be with their children. Although he was physically disconnected from his beloved Isfahan, his heart and sole remained there. While he painted many American landscapes, his main occupation remained recreating what was in his memories and ideals. On the occasion of the opening of his studio-gallery in Glendale, D. Jacobson of Glendale News-Press wrote:
If the true artist is reflected in his work, then Sumbat is a deeply loving man. His people have no sharp edges even though they are involved in such daily chores as washing clothes in a stream or cooking food. His landscapes bear a reverence for nature. Throughout all of his works, a sense of warmth and tranquility is found underneath the paint.
Towards the end of his life, Sumbat made two important trips. The first was in 1991 to Armenia - his ancestral homeland - as a special guest of the Union of Artists of Armenia. He held a major exhibit in the National Gallery of Armenia on June 1-10. An article by Vahan Harutyunian in Kroonk stated:
Armenian fine art of Iran is a singular phenomenon in the beaux arts of the Armenian Diaspora, where the classic principles and the traditions of our popular art have been kept intact. The art of Sumbat Kiureghian offers impressive evidence to this statement ... Of exceptional value are his genre scenes depicting the way of life and customs of Iranian Armenian peasants. His paintings, and his watercolors in particular, are glowingly spontaneous; they indicate the artist's great love for his subjects, their customs, the nature surrounding them, their ways of life and customs.
Sumbat's last major travel was back to Iran in 1993. He was widely and affectionately welcomed by his old friends and admirers. In Tehran, he participated in an exhibition together with younger artists. He then visited his beloved Isfahan and New Julfa. The community in New Julfa had organized a special event in his honor. Paintings were quickly gathered from private homes and an exhibition was held, where many of his old friends and admirers gathered. The memories of this last visit stayed fresh with Sumbat until his death in Los Angeles in 1999.
In 1991, a monumental book entitled Abrang-eh Iran (Iranian Watercolor) was published through the efforts of E. Nazari-Noori, an ardent lover of watercolor. It featured the five Iranian master watercolorists of the time: Sumbat, Mikail (Misha) Shahbazian, Ali-Akbar Sanati, Yervand Nahapetian and Hacoup Vartanian. Of the 40 reproductions in this book, 18 are the works of Sumbat. This book is an apt acknowledgement of Sumbat's pioneering role in the development of the Western-style watercolor art in Iran, as well as his lasting contribution in conveying the beauty of the landscape and people of this land. About the same time, the Iranian Government disallowed the exporting of original paintings by Sumbat, as they are now considered national treasures.