He was for a short time at Westminster School, but having shown a predilection for painting, he was placed under Henry De Cort, the landscape-painter.
He next worked under Samuel Drummond, A.R.A., the portrait-painter, but after about a year entered the studio of Sir Thomas Lawrence (president of the Royal Academy).
This step is said to have been taken at the suggestion of Georgiana, duchess of Devonshire; but Harlow's natural affinity to Lawrence's style in painting would be quite sufficient to account for his choice.
[1] Harlow decided to devote himself to painting, and refused an offer of a writership in the East India trade made by his father's friends.
He affected, however, an extravagance in dress far beyond his means, a superiority of knowledge, and a license of conversation which gave frequent offence even to those really interested in the development of his genius.
He possessed a power of rapid observation and a retentive memory which enabled him to perform astonishing feats, like that of painting a satisfactory portrait of a gentleman named Hare, lately dead, whom Harlow had only once met in the street.
[1] In 1815 he painted Hubert and Prince Arthur for William Leader, a wealthy M.P., who subsequently exchanged the picture for portraits of his daughters.
[1] Early in his career Harlow had made sketches of performers in the theatre, notably of the actress Sarah Siddons, who retired in 1812.
[3] A commission from the music teacher Thomas Welsh[4] to paint Siddons as Queen Katharine in Shakespeare's Henry VIII.
He was elected a member for merit of the Academy of St. Luke at Rome, an unusual distinction for an English artist, and was invited to paint a self-portrait for the Uffizi gallery of painters at Florence.
[1] His artistic progress in Italy was remarkable, but on his return to England on 13 January 1819 he was seized with a glandular affection of the throat, which being neglected, proved fatal on 4 February.
Many of his portraits were engraved, and those of James Northcote, Fuseli, Thomas Stothard, William Beechey, John Flaxman, amongst others, were highly esteemed.
The lives of the most eminent British painters and sculptors, volume 2 (London: George Bell and sons, 1879) pp.