In 1776, he was called by the Town Council to the New Greyfriar's Church of Edinburgh; and from thence translated, on the death of Mr. Plenderleith, in 1779, to the Tolbooth Church, where he became the colleague of Dr. Webster, and subsequently of Dr. Davidson.

Dr. Kemp was a clergyman of acknowledged acquirements and ability, and was distinguished by an active business disposition. He was for a great many years secretary to the Society for Propagating Christian knowledge—in which office he succeeded the Rev. Dr. John M'Farlane. The duties of the Secretaryship he discharged with great zeal and fidelity; and, by his intelligent and judicious management, tended materially to promote the highly useful and patriotic objects of the Society.

In his official capacity Dr. Kemp frequently visited the Highland districts of the country, to the improvement of which the missions of the Society were principally directed. In the summer of 1791, in particular, he undertook an extensive tour to the Highlands and Hebrides; and, that he might prosecute his journey with the greater facility, on application by the Society to the Board of Customs, the Prince of Wales brig, Captain John Campbell, was ordered to be in readiness at Oban for his use. In this vessel Dr. Kemp navigated with safety the dangerous creeks and sounds of the Western Isles— went round the point of Ardnamurchan, which stretches far into the Western Ocean, and is constantly beat by a turbulent sea—and visited all the islands of the Hebrides.

This extensive tour he accomplished in three months; and, on his return, presented a very excellent Report to the Society, not only as to the state of the schools and missions in general, but as to the cause of the destitution experienced in many of the districts, and the means by which it might be alleviated. The views entertained on the various topics embraced by the Report, and the remedial measures which it pressed on the attention of the Society, were at once liberal and enlightened, and displayed a thorough acquaintance with the capacities of the people and the resources of the country.

Dr. Kemp possessed very conciliatory and engaging manners. Wherever he went during his Highland tours he was exceedingly well received, and obtained the ready co-operation of all whose influence could possibly be of service. Even in those remote islands, where the Reformation had never penetrated, and where Roman Catholicism maintained undisputed sway, the secretary had the singular address to procure the aid and friendship of the clergy of that persuasion. While visiting the peasantry, it was no uncommon thing for him to be accompanied by the priest of the district, whose influence was highly necessary in breaking down the common prejudice against sending children to the schools of a Protestant association.

Dr. Kemp was three times married. First to a Miss Simpson, by whom he had a son and daughter; secondly, to Lady Mary Ann Carnegie (who died in 1798), daughter of the sixth Earl of Northesk; and, thirdly, to Lady Elizabeth Hope, daughter of John, second Earl of Hopetoun.

His son (who was a manufacturer) married a daughter of Sir James Colquhoun of Luss, Sheriff-Depute of Dumbartonshire—a connection which unhappily gave rise to proceedings of a rather singular nature. In the "Town Eclogue," the author (a clergyman), speaking of this marriage and Dr. Kemp's alleged familiarity with Lady Colquhoun, says—

"To a weaver's arms consigns the high born Miss;
Then greets the mother with a holy kiss."

The remainder of the attack is so scurrilous that we refrain from inserting it.

Old Sir James, becoming jealous of his own lady and Dr. Kemp, actually raised an action of divorce against her, which, of course, equally affected the character of the Doctor; and, if successful, would have subjected him in heavy damages. While this novel case of litigation was pending in Court, death very suddenly stepped in to give it the quietus, by removing the two principal actors in the drama within a few days of each other. The deaths of Sir James and the Doctor are thus recorded in the newspaper obituaries for 1805:— "April 18. At Weirbank House, near Melrose, of a stroke of palsy, aged sixty, the Rev. John Kemp, D.D., one of the ministers of the Tolbooth Church, Edinburgh, and secretary to the Society in Scotland for Propagating Christian Knowledge;"—and on the 23rd, "At Edinburgh, Sir James Colquhoun of Luss, Bart., Sheriff-Depute of Dumbartonshire." Perhaps few local matters ever excited greater interest in Edinburgh than the probable issue of this unhappy law-suit. Dr. Kemp was characterised as a second Dr. Cantwell by one party, and as the most injured man breathing by the other. Even the reality of his death became matter of dispute ; for it was affirmed and believed by not a few of his adversaries that his demise was a fiction, got up for the purpose of stifling investigation ; and it was positively asserted that, more than a year afterwards, he had been seen in Holland in the very best health and spirits. That this rumour was unfounded, may be presumed from the fact, which was well-known, of his having been struck with palsy some time prior to his death. Even admitting his demise to be a fiction, and that he was seen in Holland in the best health and spirits, it falls to be shown by what means such a miraculous recovery had been effected. The point, we think, is set at rest by the direct testimony of the late Mr. Charles Watson, undertaker (father of Dr. Watson, of Burntisland), who declared that he assisted iti putting Dr. Kemp's body into the coffin, and in screwing down the lid. Mr. Watson was one of Dr. Kemp's elders, and a person of the utmost credit.