Thomas Ryan, commonly known as 'Darby' Ryan, was born in London, England, on 12 January 1864, the son of Mary Ryan and Charles Aldworth, a gentleman. He was known by his mother's surname. Thomas Ryan and his mother left England for New Zealand, probably in 1865, and settled in Auckland, where he was educated at the Church of England Grammar School at Parnell. He left school about 1879.
Ryan was one of the outstanding rugby footballers in New Zealand during the 1880s. A member of the Grafton club, playing mostly at wing three-quarter but occasionally at centre, he represented Auckland nine times between 1882 and 1888. Included in his appearances were five matches against touring New South Wales teams and one against Great Britain. He captained Auckland in 1886.
In 1884 Ryan toured New South Wales with the first-ever New Zealand representative rugby team. He played in all eight matches on the wing and ended the tour as joint top points scorer. In a game against Wellington prior to the tourists' departure, Ryan had had the distinction of being the first player to score points for a New Zealand team when he drop-kicked a goal 10 minutes after the start. Strongly built and fast, Ryan was difficult to bring down and could drop-kick goals with either foot. He was also an excellent place-kicker.
An all-round sportsman, Ryan is said to have played cricket for the Gordon and Parnell clubs and to have belonged to the Auckland Amateur Athletic and Cycle Club and the Auckland Rowing Club. A keen yachtsman, he sailed in several racing boats and in 1897 won a series of challenge races on Sydney Harbour.
Ryan had a distinguished career as an artist, working mainly in watercolours. He was well known for his Maori portraits, which were published in the Christmas annual of the New Zealand Observer, and for his landscapes and seascapes. In 1885 he won a silver medal in the landscape painting section of the New Zealand Art Students' Association exhibition. He studied at the Académie Julian in Paris in 1892–93 and was a friend of Charles Goldie, accompanying him on sketching trips and easing his introduction into Maori society. Ryan's 1891 oil painting 'Champagne Falls, Wairakei Geyser Valley' was later hung in the Auckland City Art Gallery. He exhibited at the Auckland Society of Arts from 1884 to 1920 and at the New Zealand and South Seas Exhibition, Dunedin, in 1889–90. As a journalist Ryan contributed illustrated articles to the New Zealand Graphic.
Ryan's life outside sport and art is little known. He had moved to the Rotorua–Taupo district by 1893. In 1900 he gained his master mariner's certificate and established the first public launch services on Lakes Taupo and Rotorua; he was captain of the Tongariro for about 20 years, and a part-owner from 1900 to 1909. Ryan became a justice of the peace in 1907. About 1920 he settled on Great Barrier Island, where he farmed at Whangapara.
On 1 July 1903, at St Mary's Cathedral, Auckland, he married Mary Faith Murray of Whangarei, the daughter of Nga Puhi leader, Kamareira Te Hautakiri Wharepapa. They had two children, Thomas and Edna Faith. Ryan died of heart failure at Parnell, Auckland, on 21 February 1927, and was buried in the Purewa cemetery, Auckland. He was survived by his wife and two children.