Frank A.O. Pym was the eldest son of Charles A. Pym*, who no doubt stimulated his son's interest in natural history. Frank grew up in Grahamstown and in 1894, at the age of 16, was appointed as assistant to the director of Albany Museum, Dr S. Schonland*, who trained him in museum work. Though he did mainly routine work, such as mounting insects and plants, he also collected for the museum, for example, insects and birds during 1894-1897. As a result of his collecting he acquired first-hand knowledge of the fauna of the Eastern Cape. In 1895 he excavated shell middens at the mouth of the Rufane River (just east of Port Alfred). His finds included Khoi pottery which, with finds by others, was described by Schonland in the Records of the Albany Museum in 1903.
In 1898 the King William's Town Public Museum (which originated as the collections of the King William's Town Naturalist Society, established in 1884) had developed to such an extent that a curator was required. Dr Schonland recommended Frank Pym, who accepted the position from 1 July 1898. He was then 20 years old. That same year the museum moved into a new building which was opened to the public in October. Many additional specimens were received and the conservator of forests granted Pym a permit to shoot and trap game in the Pirie Forests for the museum until the end of June 1899. In November 1899, following the outbreak of the Anglo-Boer War (1899-1902), the volunteer unit of the Cape Medical Corps to which Pym belonged was called up for war duty. The Museum Committee granted him leave on full pay until his return in July 1900 and he used the opportunity to visit other South African museums and to collect along the Modder River. During his absence Dr H.M. Chute* attended to new acquisitions in King William's Town. From November 1900 Pym was asked to attend the meetings of the Museum Committee and in 1904, after the death of its secretary and treasurer, Mr Blewitt, he took over these duties as well. He compiled a guide to the museum about 1906, but for the next few years little was achieved because of serious financial constraints. When Dr C.J. Egan* died in 1909 Pym took over his meteorological instruments and continued his regular observations for the Cape of Good Hope Meteorological Commission. The next year he was granted four months leave of absence and at his own expense went on a shooting trip to British East Africa, where he obtained a number of antelopes and other animals new to the museum. He also took the opportunity to visit the museums at Bulawayo, Kimberley, and Durban. A collecting trip to the Melsetter district (now Chimanimani, Zimbabwe) in 1913 was less successful, owing to excessive heat and the onset of the rainy season, though some small game species were secured. A new trapdoor spider that he collected on this trip was later named Moggridgea Pymi by J. Hewitt*, director of the Albany Museum.
Pym's principal interest was in ornithology. He was a foundation member of the South African Ornithologists' Union in 1904 and represented the Cape Colony on its council from 1909 to 1913. From 1907 he collaborated with Reverend Dr Robert Godfrey* of the Pirie Mission in collecting and classifying the birds of the frontier districts. On the basis of this work Pym contributed two papers to the Journal of the South African Ornithologists' Union, "A list of the birds of the Kaffrarian frontier" (1909, Vol. 5(2), pp. 91-113) and "Birds of the Kaffrarian frontier" (1915, Vol. 11(1), pp. 29-32). The total list included over 300 species and was the first comprehensive list of the bird fauna of the region. In 1911 four bird cases were reconstructed and moved to a gallery that was later renamed the Pym Gallery. The next year he spent a week revising the exhibited bird collection of the Albany Museum.
In 1915, during World War I (1914-1918), Pym was granted leave of absence to take part in the South West Africa campaign with the Kalahari Horse. In April 1917 he was again given leave to go on active service. He signed on for the Heavy Artillery and was sent to England for training, but was discharged as medically unfit. Suffering several recurrences of malaria, which he had contracted during his collecting trip to East Africa, and also afflicted by tuberculosis, he returned to the museum in April 1918. Early in 1920 his health deteriorated rapidly. He was granted sick leave and moved to family members in Umkomaas, Kwa-Zulu Natal, where he died.
Pym was a member of the South African Association for the Advancement of Science from 1906 and, as a member of council for 1918/9, played an active role in organising the association's annual meeting in King William's Town in 1919. He wrote little, but freely gave of his knowledge to those who sought his help. He was a true naturalist and did valuable work during his more than 20 years as museum curator, while his unfailing courtesy and cheerful disposition appealed to many friends. He was a competent artist and left the museum two sketches of the Cape lion and an oil painting of the battle of Magersfontein during the Anglo-Boer War.