The career of an advocate at the bar is not an eventful one: it is simply a history of pleadings and their results, with which none but the parties concerned can be expected to feel any interest. On this account it is enough to state that every year increased Mr. Moncreiff’s professional reputation; and at a period when the most illustrious of our Scottish pleaders were at the full height of their fame (Jeffrey, Cranstoun, Cockburn, Clerk), he held a rank inferior to none. Some of them, indeed, might excel him in ready or persuasive eloquence; but this inferiority was more than counterbalanced by the depth and accuracy of his legal knowledge, and his power of turning it to the best account. In this way his professional character is thus summed up by one of that illustrious confraternity who knew, and could well appreciate his merits:—"Though a good thinker, not quick, but sound, he was a still better arguer. His reasoning powers, especially as they were chiefly seen concentrated on law, were of the very highest order. These, and his great legal knowledge, made him the best working counsel in court. The intensity of his energy arose from that of his conscientiousness. Everything was a matter of duty with him, and therefore he gave his whole soul to it. Jeffrey called him the whole duty of man. Simple, indifferent, and passive when unyoked, give him anything professional or public to perform, and he fell upon it with a fervour which made his enemies tremble, and his friends doubt if it was the same man. One of his cures for a headache was to sit down and clear up a deep legal question. With none, originally, of the faculties of speaking which seem a part of some men’s nature, zeal, practice, and the constant possession of good matter, gave him all the oratory that he required. He could in words unravel any argument, however abstruse, or disentangle any facts, however complicated, or impress any audience with the simple and serious emotions with which he dealt. And for this purpose his style, both written and spoken, was excellent—plain, clear, condensed, and nervous." In another sketch, by a different writer, we have a view of all these intellectual equipments in full vigorous action, at the time when Moncreiff was in the prime of his manhood, as well as professional reputation: "He has a countenance full of the expression of quick-sightedness and logical power, and his voice and manner of delivering himself are such as to add much to this, the natural language of his countenance. He speaks in a firm, harsh tone; and his phraseology aspires to no merit beyond that of closeness and precision. And yet, although entirely without display of imagination, and though apparently scornful to excess of every merely ornamental part of the rhetorical art, it is singular that Mr. Moncreiff should be not only a fervid and animated speaker, but infinitely more keen and fervid throughout the whole tenor of his discourse, and more given to assist his words by violence of gesture, than any of the more imaginative speakers whom I have already endeavoured to describe. When he addresses a jury, he does not seem ever to think of attacking their feelings; but he is determined and resolved that he will omit no exertion which may enable him to get the command over their reason. He plants himself before them in an attitude of open defiance: he takes it for granted that they are against him, and he must and will subdue them to his power. Wherever there is room to lay a finger, he fixes a grappling-iron, and continues to tear and tug at everything that opposes him, so that incredulity is glad to purchase repose by assenting to all he demands. . . . His choleric demeanour gives a zest to the dryness of the discussions in which he is commonly to be found engaged. His unmusical voice has so much nerve and vigour in its discords, that after hearing it on several occasions, I began to relish the grating effect it produces upon the tympanum." ["Peter’s Letters to his Kinsfolk."]

From these two delineations, although the latter is somewhat overcharged, a distinct idea may be formed of James Moncreiff in his professional character and bearing. These also had won their way to such just estimation, that on the 22d of November, 1826, he was elected dean of faculty, although the senior, and in some respects superior claims of Jeffrey to the office were against him. But in Jeffrey himself, with whom he had fought many a hard legal tournament, he found that best of all friends—a generous, openhearted antagonist--and the great critic and eloquent barrister not only maintained Mr. Moncreiff’s claims as superior to his own, but seconded his nomination. While he held this office, the dean showed his upright disinterested love of justice in a case where many in similar circumstances would have quailed. This was in reference to the West Port murders, and the trial of their infamous perpetrators, Burke and Hare. So deep was the popular abhorrence over the whole of England and Scotland on the detection of this hideous system of Thuggism, and so overwhelming was the outcry for justice—for vengeance—that it was thought no advocate could be so hardy as to plead the cause of these assassins, who were already tried and doomed by universal acclamation. It was then that several leading advocates of the Scottish bar, with Mr. Moncreiff as dean, at their head, stepped forward in defence of truth and right against the universal cry, and while the storm was at the wildest; and through their exertions the two malefactors obtained a fair dispassionate trial, in which one of them was absolved, when both might otherwise have been torn to pieces without a hearing. The exertions of the dean of faculty in this thankless and most revolting case—his earnestness to vindicate the claims of justice, whether to acquit or condemn, though a whole world might be arrayed against them—and the discriminating talent with which he sifted the evidence of the whole perplexing affair, until it stood out in all its distinct reality—were long afterwards remembered with grateful commendation, not only by his professional brethren, whom the example honoured and encouraged, but the public at large, whose hasty judgments it restrained and rebuked.

By the death of his revered father, on the 7th of August, 1827, Mr. Moncreiff succeeded to the family baronetcy, under the title of Sir James Wellwood Moncreiff of Tullibole; his elder brother, who was king’s advocate in the Admiralty Court of Malta, having died unmarried in 1813. In 1829 Sir James was appointed a lord of session, in consequence of a vacancy in the bench, occasioned by the death of Lord Alloway. This appointment was the more honourable to Sir James, that it proceeded, not from his own party, but his political opponents. They had no occasion to regret their choice, for as a judge he equalled, or perhaps even surpassed the reputation he had won as a barrister. "In the civil court," it is stated in a short notice of his life, "his judgments were admirable for learning and sagacity; and on the bench of the criminal court his dispassionate weighing of evidence, his sound appreciation of the rules of law, the impressive solemnity of his charges on great occasions, carried a conviction, and gained a confidence, which the people of Scotland have not always yielded to their judges." Before his elevation to the bench he had also risen to high public mark and importance, independently of his professional displays, by his speeches at public meetings, on affairs both political and ecclesiastical. This was especially the case at the great meeting held in Edinburgh in favour of Catholic Emancipation; and when Dr. Chalmers and Lord Jeffrey delivered their eloquent and memorable speeches on that important occasion, the first resolution had been previously moved and enforced with great power by Sir James Moncreiff. It was, however, as a member of the General Assembly of the Church of Scotland that his great talents for investigation and debate, combined with his well-known integrity, were chiefly valued; so that, on several important occasions, he was called to lead the deliberations of that august body.

So close a connection with the church, and such a hearty devotedness to its interests, which marked the professional career of Lord Moncreiff, is not to be wondered at when we remember his clerical descent through not less than seven generations! Like his father, also, he adhered to that party in the church known by the title of Evangelical, in opposition to the Moderate side, which might be called the Toryism of the Scottish Kirk. While he held the office of a ruling elder, his attendance at church courts was frequent and his aid effectual, and he had the satisfaction to witness the rise, from year to year, of those principles of religious doctrine and ecclesiastical polity with which he was connected. At length, when his party had acquired such strength as to bring their controversy to a decisive issue upon the great question of patronage, he was called, in 1832, to give evidence before a select committee of the House of Commons, which was appointed to inquire into the origin and exercise of church patronage in Scotland. His lordship’s answers to the searching questions which were put to him on his examination, the flood of light which he threw upon this difficult subject, and the simple, earnest, impressive language and manner in which his testimony was delivered, were long afterwards remembered. For a considerable time before the Disruption he had retired from the conflict in consequence of his judicial position; and when at last it occurred, in 1843, his attention was too mournfully engrossed by the death of his lady, which happened at the same period, to allow him to join in the events of that great movement. After the Disruption, although he ceased to be an elder, he continued to hold church-membership in the Free Church of Scotland, with whose leading principles his whole course of life had been identified.

On nearing the venerable age of seventy-five, Lord Moncreiff began to yield to the decay of nature; and for several weeks before he died, the state of his health was such, that although the physicians held out hopes of his recovery, he felt assured that his end was at hand—a result which he contemplated without dismay, and for which he prepared with Christian resignation and confidence. His death occurred at his house in Moray Place, Edinburgh, on the afternoon of March 30, 1851, and his remains were interred in the Dean Cemetery, within a few feet of the grave of his old friend, Lord Jeffrey. His character is thus briefly and emphatically summed up by Lord Cockburn: "I am not aware how his moral nature could have been improved. A truer friend, a more upright judge, or a more affectionate man, could not be."