Charles Robert Leslie was captivated by theatrical art, especially by great masters such as William Shakespeare, Miguel Cervantes, Molière and Henry Fielding. With paintings of theatrical art, Leslie was able to express his love for the theatrical world, which he portrayed with great precision in his paintings.

Charles Robert Leslie often drew his motifs from Shakespeare's plays (including The Merry Wives of Windsor) and Cervantes' (including Sancho Panza). His most famous paintings include "Uncle Toby and the Widow Wadman" (circa 1829-1830, Tate Gallery, London).
Leslie entertained sincere and genuine feelings for the theater world, which made it easier for him to portray the authors' different perceptions of beauty, characters and comedy in the various dramatizations.

In 1821, Leslie was elected to belong to the outer circle of friends around the Royal Academy of Arts in London.
Five years later, he was appointed a full member of the Royal Academy of Arts and was awarded the title of R.A., as proof that he belonged and officially became a member of the Royal Academy of Arts.

Several of Leslie's works of art were acquired by the American philanthropist James Lenox (1800-1880), whose father was very wealthy. At his father's death in 1839, James Lenox inherited a substantial fortune; one million dollars in cash and 30 acres of land, which was located between the Fourth and Fifth Avenues in Manhattan.
James Lenox then chose to retire, in connection with his father's death, and instead dedicated his life to art and book collecting, as a full-time job. He founded the Lenox Library with, among other things, Charles Robert Leslie's paintings. The art collection is still intact today. Today, these works of art by Charles Robert Leslie belong to the New York Public Library, located at Bryant Park in New York City.

Charles Robert Leslie R.A. is represented in a large number of public art collections, for example Tate Museum London, National Portrait Gallery London, Victoria and Albert Museum London, Royal Shakespeare Theater Statford-upon-Avon, Harris Museum Preston, The Wellington Collection London, The Marble Hill House Twickenham, Swansea Museum, Hunterian Museum London, Shandy Hall York, Abbotsford House Melrose, Walker Art Gallery Liverpool, National Trust Petworth, Ulster Museum Belfast, Royal Academy of Arts London, Yale Art Center in Connecticut USA, Hampton Court Palace East Molesey, National Trust West Sussex, The New York Public Library and The National Trust for Scotland, Ellon.