Daniel Nilva was born in New York City on March 7, 1914, the only child of Joseph Nilva and Eva Bloom, Russian Jewish immigrants. Joseph Nilva worked as a painter in a shipyard, and gilding and painting moldings of buildings--and as a pushcart peddler. Eva Nilva worked as a fan dancer on the popular stage; she taught Nilva to dance and he performed on stage with her as a child. Nilva's parents were divorced by the time he was in his teens, and may have separated earlier. In any case, it appears that between the ages of six and thirteen he was moved around considerably, living with each of his parents in turn, and then sent to board with and attend school with friends in the Midwest, in Omaha and Chicago, and finally to a farm in Roscoe, New York, where he lived until he completed high school. Nilva became close to the farm family and a lifelong friend of Leon Becker (later a criminal court judge), who also boarded at the farm. It was here that Nilva acquired his first camera, a Brownie box camera.

The 1930s were a formative time in Nilva's life personally, politically, and professionally. He returned to New York City, where he attended Cooper Union, studying engineering for four years, although he did not graduate. He married Alice Mildred ("Millie") Elkes and became friends with three men to whom he remained close the rest of his life--Bernard Seaman, a labor cartoonist, Morris Stone, later an official with the American Arbitration Association, and Dr. Valentine Gregory Burtan, a heart specialist who had been imprisoned on a counterfeiting charge. Nilva also joined the Communist Party Opposition (a splinter group of the Communist Party, led by Jay Lovestone and also known as the Independent Communist Labor League and Independent Labor League of America), and in early 1933 he went to work as a photographer for the Education Department of Local 22, Dressmakers, of the International Ladies' Garment Workers Union (ILGWU). Millie Nilva appears also to have been associated with Local 22 and may have worked there. Nilva documented functions and activities of the Local with his camera and photographed for the ILGWU newspaper, Justice. He did freelance work for the Bookkeepers Stenographers and Accountants Union's newspaper, The Ledger, as well. His primary cameras were a Leica Model G and a 4x5 Speed Graphic.

In 1937, Nilva's employment with Local 22 came to an end. The following year he sat for and passed New York City's civil service examination for photographers. At the recommendation of Jay Lovestone, he applied directly for a job with the president of the Civil Service Commission, but evidently was not successful. Nilva was rejected for military service in World War II because of his extremely poor eyesight. During the war, he worked in New Orleans at an aircraft factory. After that he had considerable difficulty finding work before landing a full-time job at the New York Public Library in an unknown capacity. By the 1950s, however, Nilva was working full-time as a freelance photographer in New York City, and maintained a studio at at least one address (Broadway and 27th Street). His clients included a variety of labor unions and progressive organizations. Nilva's marriage to Millie Nilva did not last long. The couple had no children and were separated for nearly twenty years before divorcing.

In September 1951, Nilva and his friend, Bernard Seaman, signed on to work as merchant seamen, on the MS Hurricane, which sailed from Rotterdam on the fifth of that month, and arrived in New York on the 16th—Seaman as a deckhand, and Nilva in an unknown capacity. It was the first time, and probably the last, that either of them had worked on a ship. Nilva used his camera to document the work and living conditions of their fellow workers.

In 1964 Nilva married again, this time to Sheila Cole, a writer; they had two daughters. Their first few years together were a financial struggle, in part because of medical bills occasioned by a heart attack suffered by Nilva and because the ill-health caused by the heart attack forced him to cut back on his photography. By the mid-1960s, however, Sheila Nilva had opened an antique shop, managed by both of them, that featured cameras and photographica. The shop eventually became successful enough to support the family, and the Nilvas -- partly underwritten by Sheila Nilva's freelance assignments as a travel writer -- were also able to travel extensively in North Africa and Europe, as well as throughout the United States and the Caribbean. Nilva died September 15, 1984, of a heart attack, at the age of seventy.