Trevor Lloyd was born at Wade (Silverdale), near Auckland, New Zealand, on 21 December 1863, the son of Henry Lloyd, a farmer, and his wife, Hannah Miles. After attending the local school Lloyd worked on the family farm. Inspired by his father, who was an amateur artist, he began filling small sketch-books with drawings of his immediate environment and with caricatures of his family and friends. Before long he was doing oil paintings based on the sketches.
Among Lloyd's surviving paintings is one showing a young man shaving in a singlet and working trousers; he is in a one-roomed cottage surrounded by everyday objects and could easily have been Lloyd at this stage of his life. In 1883 Lloyd exhibited with the Auckland Society of Arts. Although essentially self-taught, he may have had some lessons with the artist Louis John Steele. For much of his career Lloyd had no thumb on his writing hand and was blind in his left eye.
On 6 June 1894 Trevor Lloyd married Emily Lamont at Wainui, near Wade. They were to have two daughters, Constance and Olive. Lloyd exhibited again with the Auckland Society of Arts in 1896, 1898 and 1899. In the early 1900s the family moved to Auckland where Lloyd began earning a living from his art. His first commission was to illustrate stories and articles in the New Zealand Illustrated Magazine. He also produced a series of illustrations for the New Zealand Graphic. Early in 1903 he joined the Auckland Weekly News as an illustrator, graphic artist and cartoonist. From 1904 his cartoons also appeared in the New Zealand Herald. Initially he drew mainly political cartoons and made sketches of indoor and night events, which were then beyond the scope of the camera. However, his cartoons soon covered a variety of topical as well as political issues. During the 1905 All Black tour to Britain, he drew one of the first New Zealand cartoon using the kiwi as a symbol for New Zealand. Lloyd also caught the public imagination by dubbing the New Zealand Railways the 'New Zealand Snailways'. In 1907 he exhibited once more with the Auckland Society of Arts.
Most of Lloyd's work for the Weekly News was done in line and wash. However, in 1921 he began to contribute pen-and-ink drawings to the Saturday supplement of the New Zealand Herald. Lloyd's daughters both attended the Elam School of Art, and after seeing samples of their print-making, he took up etching and drypoint. Over the years he produced sepia etchings of Maori subjects, the New Zealand bush and Auckland's environs. It is perhaps for his etchings that he is best known. He went on painting trips to the volcanic region of the central North Island and produced etchings and watercolours of the area. Among his most popular and unique images are a series of bushscapes populated with the little people of the bush, based on the patupaiarehe of the Maori. In 1927 he exhibited etchings 'of native bush and Maori fancies' at the New Zealand Academy of Fine Arts exhibition. He was also an occasional illustrator of books.
Lloyd was particularly interested in Maori culture and language. He became well known for his decorative borders in the Christmas number of the Auckland Weekly News, which appeared around photographic montages and featured New Zealand flora, fauna and Maori motifs. Lloyd also used Maori motifs and people in his cartoons. The family bach, in the Waitakere Range west of Auckland, was built in the shape of a Maori meeting house with Lloyd supplying the carvings. He chose the name Whare Tane for the family home and accumulated a considerable collection of Maori artefacts. He found many pieces while fossicking with his dog along and around the beaches, pa sites and caves of Auckland's rugged west coast. A significant part of the collection is now held by the Auckland Institute and Museum.
In November 1936 Trevor Lloyd retired from the staff of the New Zealand Herald and the Auckland Weekly News. He died in Auckland the following year on 11 September, survived by his wife and daughters. Lloyd had been a pioneer of etching in New Zealand and one of the country's leading political cartoonists for 32 years. A retrospective exhibition covering all aspects of his work was held at the Rotorua Art Gallery in 1983. In the same year Lloyd's daughter Constance presented one of his large watercolours to the Auckland City Art Gallery in his memory. The painting, possibly his most famous, shows the birds and creatures of the bush lamenting the death of the last moa. Lloyd is represented in most public collections of New Zealand.