Niebour was a childhood friend of Leslie Illingworth, the two attending grammar school Barry County School (also attended by another cartoonist, David Gwilym John, creator of 'Dai Lossin'). Illingworth went on to join the Western Mail, published in Cardifff, and attended Cardiff School of Art. Niebour instead joined the Merchant Navy and in 1920-21 served as a Laundry Boy aboard the Ormonde.
Ronald Niebour, circa 1920
He was persuaded by his family to become a teacher and, encouraged by his uncle, a superintendent of handicraft teaching, he studied metalwork and woodwork, and then spent three years teaching handicrafts at schools in Birmingham, Weymouth and Kendal.
He was self-taught as an artist and began selling caertoons, producing football cartoons for the Barry Dock News and Cardiff Evening Express. He also worked for the Oxford Mail, drawing local sporting cartoons, caricatures and a daily children's strip, before moving onto the staff of the Birmingham Gazette and Birmingham Evening Despatch. Here he tackled numerous jobs from retouching photographs to sketching any illustrations required.
He submitted sketches to the Daily Mail and, in 1938, was offered the opportunity to illustrated the paper's woman's page and gardening notes. He joined the staff in September 1938, moving from his home in King's Heath (199 May Lane, King's Heath 14) to London. After the outbreak of war he switched to drawing pocket cartoons, which proved to be his metier, and he was named by London Opinion in 1942, as one of the most popular pocket cartoonists in the national press. In 1945, a cutting of a "Neb" cartoon from the Daily Mail was found in the ruins of Hitler's Chancellery.
Niebour continued to draw for the Daily Mail until 1960. He also contributed to Punch and produced advertisements for Winsor & Newton.
He was married to Evelyn Mary Ursula Kavanagh in 1942 in Glamorgan, Wales. He died at his home in Benajarafe, near Malaga, Spain, on 19 July 1972, aged 69.