John Keppie was born in Glasgow on 4 August 1862, the fourth child and elder son (his brother James was born c.1866) of John Keppie, a wealthy tobacco importer who came from Haddington and had houses in Hillhead and Prestwick. His mother was Helen Cuthbertson Hopkins, who originated from Galston, Ayrshire. Keppie was educated at Ayr Academy, as he was brought up in Prestwick rather than Hillhead. He was articled to Campbell Douglas and Sellars c.1880 and somewhat unusually attended classes at the University of Glasgow as well as Glasgow School of Art. Although his dossier is missing he appears to have enrolled at the Ecole des Beaux-Arts and the Atelier Jean Louis Pascal in 1885 and remained there until at least the autumn of 1886 when he travelled in Northern Italy. He did not return afterwards as his nomination paper states that he spent one year with Pascal. As an accomplished draughtsman and a fine watercolourist he had remarkable success in the Tite Prize competitions, winning its silver medals in that year and again in 1887. On his return to the Campbell Douglas & Sellars office he assisted Sellars with the firm's entry for the Glasgow International Exhibition of 1888, the competition for which had been advertised in January 1887 and was won on 31 March 1887 with a weather-boarded design with galvanised metal domes in a Moorish, probably basically French colonial, idiom.
While the Exhibition buildings were completed on schedule the project was fraught with difficulties as Campbell Douglas became seriously ill and was unable to come downstairs to the office for months. This put a severe strain on Sellars and Keppie, and while on site a nail pierced Sellars's boot. This was neglected from want of time and ultimately brought about Sellars's death from blood poisoning on 9 October 1888.
Campbell Douglas was then barely recovered. He decided to take his chief draughtsman Alexander Morrison into partnership. Keppie had worked more closely with Sellars, and by what appears to have been an amicable arrangement he was taken into partnership by John Honeyman whose practice was then chronically short of work and money: he effectively refounded the practice, Douglas having allowed him to take the commission for the uncompleted Anderson's College of Medicine with him as a setting-up commission. Douglas & Morrison retained the other work of the practice, although over time more clients migrated to Keppie's. The matter was handled discreetly and nothing of what this unusual arrangement was about became common knowledge.
At the end of his first year in practice Keppie's father died and he and his brother found themselves responsible for their mother and four sisters: of his sisters he was closest to the youngest, Jessie, born in 1868. While his father's death gave Keppie and his brother both the money and the freedom to do what they wanted, these family responsibilities also proved a bit of a tie. He had hoped to marry Helen Law but in the event she became engaged to the painter E A Walton.
In the early to mid 1890s Herbert McNair, whom he had inherited from Honeyman, and Charles Rennie Mackintosh, whom he had recruited in April 1889,were frequently guests working week-ends at Prestwick, while Jessie brought a circle of friends from Glasgow School of Art who were put up at two bungalows rented by her brother at Dunure ('The Roaring Camp'). There Mackintosh formed some sort of attachment to Jessie, while the well-off MacNair courted Frances Macdonald. In the event Mackintosh transferred his affections to Frances's elder sister Margaret and with that event this group (The Immortals) seems to have disbanded: Mackintosh, MacNair and the Macdonald sisters forming a smaller group known as The Four. Keppie did not marry any of Jessie's circle, and after what may have been a further disappointment with Bessie MacNicol, one of whose paintings he bought, he never married. From an early age he became a close friend of the painter Edward Atkinson Hornel, habitually bringing in the New Year with him at Kirkcudbright. Within the architectural profession he was closest to John Archibald Campbell, another product of Pascal's atelier, who was also a bachelor. Until Campbell died in 1909 he was an occasional houseguest at Bridge of Weir for golf.
Although Keppie remained a superb draughtsman and watercolourist, from the early 1890s Keppie was at first content to let Mackintosh do most of the designing, particularly on competition work. Even after Mackintosh left Jessie for Margaret, an event which apparently caused Jessie long-lasting distress, this arrangement continued although the working weekends at Prestwick necessarily came to an end: personal problems were set aside in the desire to win competitions and build up the practice.
On 1 January 1901 John Honeyman was deemed to have retired although he was in fact in the office a great deal in those years because of the joint commission with Dr Thomas Ross to restore the choir and transepts of Iona Cathedral for the Iona Cathedral trustees carried out in 1902-04. Charles Rennie Mackintosh was then taken into partnership, the practice title becoming Honeyman Keppie & Mackintosh from 1901. The partnership agreement was for ten years and may have taken some time to negotiate as it was retrospective, drawn up in Keppie's handwriting as late as 10 October 1901. For the first three years, from 1901 to 1903, Honeyman was to receive half the practice's profits. From the remaining half Keppie was to be paid two-thirds and Mackintosh one third. Honeyman was then bought out and for the next two years, 1904 and 1905, Keppie was to receive three-fifths of the profits and Mackintosh two fifths. Mackintosh thus did not have to put up any capital, but the equal division of the profits from 1906 was to lead to problems later as Keppie's clientele was much larger, and was to remain so.
Mackintosh's partnership had the perhaps unexpected effect of a redivision of design responsibilities within the practice. Keppie returned to the drawing-board for his own clients rather than delegating to Mackintosh. Except for the completion of Glasgow School of Art and the firm's commission for Scotland Street School, Mackintosh thereafter designed for his own clients only. This resulted in a series of free Renaissance and Scots Renaissance buildings for Keppie's clients in the style Keppie and Mackintosh had developed some eight to nine years earlier, ideas from old competition projects sometimes being recycled as at Parkhead Cross Savings Bank. Some of these buildings, particularly the McConnell buildings on Hope Street were of considerable merit if rather less up to date than those of Burnet, Campbell and Paterson; others like Simpson's on Sauchiehall Street had somewhat ungainly proportions and crowded details. But professionally Keppie's stock rose: he was belatedly admitted FRIBA in 1904, an event which may have been connected with Alexander Beith McDonald's proposal to employ him as assessor for the Mitchell Library in 1904, a competition which was conducted according to RIBA rules.
Keppie was soon to find that a brilliant designer with an international reputation was not always the right partner for a more mundane Glasgow clientele. Mackintosh's commissions for interior work in Germany and Austria led to Mackintosh suggesting that he might spend part of the year in Vienna which Keppie declined to agree to. That occasioned some disappointment but it blew over. The relationship between Keppie and Mackintosh was much more seriously strained at Scotland Street School, where in November 1905 the School Board of Glasgow wrote a rebuke which made any further commission from the Board unlikely. Nevertheless relations between them were still good enough for Keppie to propose Mackintosh for Fellowship of the RIBA in September 1906 and even get Burnet to sign his nomination paper: this document is of some interest as he allowed Mackintosh to state that he had been a principal since 1898 to ensure his admission after only five years as a partner. He also lent Mackintosh a substantial sum to enable him to buy and remodel his house on Florentine Terrace in that same year. But further problems were to arise with the building committee of Glasgow School of Art in February: the real problem after the School was completed in 1909 was that thereafter Mackintosh had very few commissions of his own, a situation aggravated by the increment tax on new developments in the Finance Act of 1909: newly commissioned work was halved in 1910 and again in 1911, remaining at a low level through 1912 and 1913. This made success in competitions for public projects all the more important and Mackintosh's inability to complete the firm's invited submission for the Jordanhill Training College in time became the catalyst for the dissolution of the partnership. Mackintosh had no drawings at all for the demonstration school element of the competition. It was drawn out by Andrew Graham Henderson whom Mackintosh had recruited in May 1904, and on whom Keppie had increasingly come to depend. Henderson told Keppie that he would not stay if Mackintosh remained as partner: Keppie was not a man to respond to threats from staff, but Mackintosh's depression and lack of commissions had already caused him to make an analysis of the accounts of the partnership from 1901 to 1911, the orihinal partnership agreement having expired on 1 January 1910. This showed that Mackintosh had introduced £4,934 of new business during that period and Keppie £16,303, and Mackintosh's share of the profits had been £5,467. Nothing ever leaked out about what was said. The partnership is believed to have been dissolved in June 1913 although Mackintosh still represented the firm at a meeting in July when Henderson's design for the demonstration school was accepted, the commissions for the main College and the hostels going to David Barclay and Andrew Balfour. Mackintosh then left to set up his own practice although the partnership was not formally dissolved until June 1914. A month earlier Keppie had sent Mackintosh a cheque for £250 as his share of the competition award. The surviving correspondence from these years does not suggest any animosity on either side. It was not until 1920 that Keppie gently hinted to Mackintosh that the house in Florentine Terrace might be sold.
On the dissolution of the partnership with Mackintosh, the practice reverted to being simply Honeyman & Keppie with Keppie as sole partner. Henderson won the major competition for the reconstruction of Glasgow Cross in 1914 but was called up for military service shortly thereafter, Keppie allowing him a retainer of £216 p.a. In 1916 Henderson was shot through the right elbow and had to learn to draw with his left hand. He then returned to the office as partner, the practice taking the title of John Keppie & Henderson.
Henderson did most of the design work from 1917 onwards, Keppie's role becoming more managerial. But he was elected RSA in 1920 and continued to take a very active role in professional matters, particularly as a governor of Glasgow School of Art. He had been Deacon of the Incorporation of Wrights at the Trades House in 1906 and president of the Glasgow Institute of Architects in 1905. He was president again in 1919-20 and President of the Royal Incorporation of Architects in Scotland in 1924-26; and as a Council Member of the RIBA he became its vice president in 1929. He generously endowed the John Honeyman Studentships in architecture and in Sculpture in 1923 and did much to promote the career of Benno Schotz: despite the difference in age they became Saturday sketching companions. Ultimately Keppie's long service as a governor of Glasgow School of Art ended in his chairmanship in 1930-32: his regime was marked by a long-standing antipathy to the professor of Architecture, Thomas Harold Hughes, who escaped by transferring his service to the Royal College and setting up a joint Board of Studies in 1924.
In 1930 Alex Smellie, the practice's industrial architect and structural engineer, was taken into partnership. Thereafter Keppie spent much of his time presiding over Glasgow Art Club where he was known as King John: he kept a watchful eye on those who came and went and mercilessly teased some of its members, particularly William Whitie in respect of the Mitchell Library award.
Keppie's formal retirement from the practice seems to have been in 1937, but the effective date may have been 1935 as from 1936 he exhibited from his house at 16 Hamilton Park Avenue. This house was given up after war broke out in 1939. Thereafter he lived at Haddington Park in Prestwick with his sister Jessie. In his last years he is said to have been sometimes a bit wandered and of uncertain temper, at least partly because the Second World War had curtailed his freedom to travel abroad, Spain (from 1897), Egypt (from 1900), Italy (from 1911) and Morocco (from 1933) being favourite venues for sketching and watercolours. When he was elected full Academician in 1931 it was as much for his watercolours as his architecture. At both the RSA and the RGI his exhibits were predominantly watercolours.
Keppie died at his house, Haddington Park West, Prestwick on 28 April 1945. He left £40,931 3s 6d, bequeathing £2,000 to Graham Henderson and his MacNicol picture to Glasgow Art Gallery. He was buried in Prestwick and Monkton Cemetery where a characteristic early Renaissance monument commemorates him and his sisters. As an architect he was not among the most gifted of those who went to the Ecole, but he has been an unfairly maligned man.