Leitch was born in Glasgow, the son of a soldier who had previously been a sailor. Leitch soon developed a strong inclination for art, and used to practice drawing at night with David Macnee, afterwards president of the Scottish Academy. After a good general education, he found employment in a lawyer’s office, then as a weaver, then as an apprentice to a Mr. Harbut, house-painter and decorator. In 1824 he was engaged as a scene-painter at the Theatre Royal, Glasgow, and married Susannah Smellie, who bore him five sons and two daughters. The theatre failing, he spent two years at Mauchline, painting snuff boxes, and then moved to London, where he made the acquaintance of artists David Roberts and Clarkson Stanfield, and obtained employment as a scene-painter at the Queen’s Theatre (now demolished) on Charlotte Street. He had some lessons from Copley Fielding, and was employed by Mr. Anderden, a stockbroker, to make drawings for a work he was writing Church of Santa Maria Del Carmine, Naples (1840) After exhibiting two drawings at the Society of British Artists in 1832, he travelled to the continent in 1833, passing through the Netherlands, Germany, and Switzerland to Italy. While in Venice he met and became friends with the Hungarian painter, Miklós Barabás; They toured and painted in the Lago Maggiore region in 1834, and Leitch was a great influence on Barabás’s future work. After an absence of four years, during which Leitch supported himself mainly by teaching, and had visited the principal cities of Italy, and made numerous sketches there and in Sicily, he returned to London in July 1837. He now devoted himself almost entirely to teaching and working in watercolours. He had great success as a teacher and could count many members of the aristocracy amongst his pupils. He was introduced to Queen Victoria by Lady Canning and became the drawing master to her majesty and the royal family for 22 years.