Roderick Syme was born in Hawera on 24 February 1900, the son of James Dodds Syme, a joinery foreman, and his wife, Ethel Mary King. After completing his schooling at Hawera District High School, he was a probationary teacher at Feilding District High School in 1916 and 1917. He then went to the Teachers' Training College, Wellington, and studied part time at Victoria University College. On returning to Taranaki in 1919 he took up a position in Hawera as an instructor in agriculture for the Taranaki Education Board.
In 1920 Rod Syme attended the meeting in Hawera that saw the establishment of New Zealand's first boys' and girls' agricultural clubs. The scheme, initiated by C. H. Walker, agriculture editor of the Hawera Star, and G. H. Buckeridge, secretary of the local branch of the New Zealand Farmers’ Union, aimed at encouraging schoolchildren to take an active interest in the land and its products. It was initially adopted by 19 South Taranaki schools. The first year's programme was confined to crop-growing projects, but in 1921 calf-rearing was added and North Taranaki schools joined the scheme; they were followed by schools throughout the country. For the next four decades Syme was an impassioned advocate of the agricultural clubs and the training they gave to both rural and town children.
As agricultural instructor, Syme advised teachers on how to implement nature study, science and horticulture programmes in schools and classrooms. He also supervised school gardening and the layout of school grounds. He tried, as he later said, 'to make children more aware of the wonders of nature – a flower opening, a seed germinating, snow and ice under a microscope, and dew on a spider’s web’. As well as passing on his botanical knowledge, he fostered a concern for the environment in several generations of Taranaki school pupils. The planting at Turuturumokai reserve on the outskirts of Hawera of thousands of native trees, grown by local schoolchildren as a 1940 Centennial project, was one of the many beautification schemes he initiated. In 1952 he became the senior agricultural instructor in Taranaki; he held the position until he retired in 1961.
Outside his work, Syme achieved distinction in mountaineering. At 19 he made his first climb on the mountain at his doorstep and began a 75-year association with Mt Egmont, its clubs and huts. His first full ascent was in 1921 and he completed his 227th and final ascent of the peak, in January 1971, accompanied by his two sons and eldest grandchild. He made his first expedition to the Southern Alps in 1926–27 with W. G. Mace and H. F. Allan. This was followed, in 1931, by a climb that involved a new ridge route on Mt Tasman. The ridge now bears Syme's name. In 1931 he also won the New Zealand long-distance skiing championship.
Although Syme's climbing and skiing exploits are legendary in mountaineering circles, it is his association with alpine sports administration that is more widely known. He formed the Mt Egmont Alpine Club in 1928 and was club captain for 24 years and editor of the club journal for 50 years. In 1929–30 he and other club members backpacked all the construction materials onto the site, then erected Syme Hut on Fanthams Peak. He served as an office holder of the Ruapehu Ski Club, the New Zealand Alpine Club and the New Zealand Ski Council, and was a life member of the Ski Club of Great Britain. He was also one of the prime movers in establishing the Federated Mountain Clubs of New Zealand, and was instrumental in setting up a search and rescue organisation in Taranaki.
From 1928, when he was appointed to the South Committee of the Egmont National Park Board, Rod Syme was deeply involved in national parks administration. He was a member of the Egmont National Park Board (1945–54), the Tongariro National Park Board (1948–54) and the National Parks Authority of New Zealand (1954–74). He was made an MBE in 1955 for his services to mountaineering and agricultural education.
Rod Syme's interest in climbing, tramping and gardening were shared by his wife, Evelyn May Buist, whom he married in Hawera on 14 May 1936. The couple were very good tennis players and also belonged to the Hawera Aero Club. For many years Syme was on the Taranaki Regional Committee of the New Zealand Historic Places Trust and in 1986 received the Trust's Certificate of Meritorious Service. He was a keen member of the Hawera Savage Club, and he served for 15 years as a Hawera borough councillor, and for 12 as a member of the Taranaki Harbour Board.
He was a fellow of the Royal Horticultural Society, the Royal Geographical Society and an associate of honour of the Royal New Zealand Institute of Horticulture. In 1977 he was awarded a Nature Conservation Council citation and in 1986 he received the Loder Cup for his work in protecting New Zealand native flora.
Rod Syme was a tall, fit man who was not easily flustered. Nothing delighted him more than to discuss plants and shrubs with visitors in his extensive garden or to encourage others to experience and appreciate the alpine environment. He died in Hawera, aged 94, on 2 May 1994, survived by his two sons. Evelyn Syme had died in 1992.