Dr. McLean complied with the advice of his instructor, and became a pupil of Queen’s Museum.  In this venerated institution, shedding abroad its enlightening influence on Western North Carolina, many of the leading patriots of the Revolution acquired their principal educational training.  Its president, Dr. McWhorter, was not only an eminent preacher of the gospel, but was also an ardent patriot, and never failed, on suitable occasions, to discuss the politics of the day, and instil into the minds of his youthful pupils the essential principles of civil and religious liberty.  His sentiments in this respect were so generally known, that it is said Cornwallis previous to his entrance into Charlotte in 1780, was extremely anxious to enfold him in his embraces.  Dr. McLean remained in this institution of learning about two years and then returned home.  Having made up his mind to become a physician during his collegiate course, he gathered all the medical books he could procure at that period, and diligently devoted his time to their study.  In this stage of his early preparation for future usefulness, Dr. Joseph Blythe, a distinguished surgeon in the Continental Army, wrote to him in terms of warmest friendship, and offered him the position of “surgeon’s mate.”  This offer he accepted, repaired to Charlotte, and they both marched with the army to James Island, near Charleston.  In this immediate vicinity at Stono (the narrow river or inlet, which separates John’s Island from the main land) a severe but indecisive battle had been fought between a detachment of General Lincoln’s army and the British, under General Prevost, in June, 1779.  At the time of Dr. McLean’s arrival at James Island, many soldiers were sick with the pestilential “camp fever” of that sultry climate, or were suffering from the wounds of battle at the army hospital.  Some of these sufferers were from Lincoln and Mecklenburg counties, with whom he was personally acquainted.  Under judicious medical treatment he was pleased to see most of them, in a short time, restored to health and ready for the future service of their country.

In the summer and fall of 1780 Dr. McLean was constantly with the Southern army watching the movements of Ferguson in the upper Tory settlements of South Carolina, previous to his defeat and death at King’s Mountain.  After that battle he went to Charlotte to wait on the sick and the wounded at that place.

In 1781 he was with General Greene’s army, near Camden, and at other military encampments requiring his services.  In all of these responsible positions he continued to faithfully discharge the duties of “Surgeon’s Mate,” or Assistant Surgeon, until the close of the Revolution.

Having completed his preparatory studies Dr. McLean went to the medical University of Pennsylvania at Philadelphia, and received from that venerable institution his diploma in 1787.  In a short time after his arrival at home he purchased a farm in the “South Point” neighborhood, soon engaged in an extensive practice (frequently charitable) and became eminent in his profession.