Lyall was born in Edinburgh the son of James Lyall and his wife Janet Lyall, née Pirrie, and was educated at Edinburgh High School, Glasgow University and Edinburgh University, and for the ministry at the Theological Hall of the United Presbyterian Church. He served as a home missionary in Glasgow, Edinburgh and Alloa for 10 years before being called to Adelaide as a long overdue replacement for Rev. Ralph Drummond at the United Presbyterian Church on Gouger Street. They sailed to Melbourne aboard Ellen Stuart, arriving on 7 September, and during their enforced stopover he took a couple of services, and arrived in Adelaide aboard Burra Burra by 25 September 1857 and took his first service there on 27 September 1857. The church enjoyed a steady increase in membership numbers. He applied himself vigorously to his new community, as a founder of the multi-faith City Mission, and Bush Mission Society, and was prominent at official functions of other Protestant denominations. He was active in the Temperance cause, the South Australian Sunday School Teachers' Union, London Missionary Society, British and Foreign Bible Society, Missions for the Heathen, Aborigines' Friends' Association and others. He brought to his congregation influential, wealthy and generous members: W. W. Hughes, John Duncan, David Murray and John Gordon. Mrs. Lyall was also active in temperance and other worthy causes, amongst them the Women's Christian Temperance Union and the Presbyterian Women's Missionary Union in South Australia, of which she was founding president. In 1873 and 1874 he took a long holiday in Great Britain and the Continent, most of their expenses being met by the congregation. In January 1883 a site was purchased for £700 for a new church on Flinders Street directly opposite the Baptist church which was completed a few years earlier. The foundation stone of Flinders Street Church was laid by Rev. Ralph Drummond on 5 September 1864. The building was completed a year later and the first service was held there by Rev. William Richey on 27 October 1865. A spire was erected the following year, and a manse was built next door in the same year. He was moderator of the Federal Assembly of the Presbyterian Churches of Australia, and in that capacity visited the New Hebrides Mission, where his brother-in-law Dr. John Gibson Paton was a missionary, and attended the annual mission meeting at Aneityum. He retired in November 1897, and was presented with a retirement gift of £2,000. His wife died in 1902, and he moved to Mentone, Victoria, where he died a few years later following a successful surgical operation.
Family
James Lyall married Helen Whitecross of Kew, Victoria in England on 29 April 1857. Their family included:
Helen Lyall married William Hanna Hoggarth in 1882
James Lyall married Ellen "Lillie" Morrey
John Whitecross Lyall married Christina Cattanach Macintosh in 1881, and to McIntosh, of Kincraig, Narracoorte. He was manager of the Commercial Bank of Adelaide at Yankalilla at the time of its collapse, in 1886 he was tried for embezzling £1245 after being apparently burgled, found "not guilty". He married again, to a daughter of William McLeod, a squatter of New South Wales.
William Paton Lyall married Christina "Teenie" McKenzie on 12 April 1897, moved to Western Australia. He was for a time of editor of the Seymour Telegraph, died on the Busselton beach from unknown causes. She married again, to George Sydney Olivey on 18 December 1909, drowned herself in the Swan River.