According to his brother, he took "a particular delight in drawing flowers, fruits and other objects of natural history", becoming "so great a proficient in that stile of painting, as to attract the notice of the most celebrated botanists.

"[6][8] While no direct evidence exists that Parkinson received formal training in art, he has been connected to William Delacour, who taught drawing and design at the Trustees' Academy, and may have been influenced by other Edinburgh artists.

[13][14] Parkinson began to give drawing lessons,[15] and the Scottish nurseryman James Lee, a fellow Quaker, employed him as teacher to his daughter Ann.

[13] Parkinson produced copies of some animal paintings in the collection of Joan Gideon Loten, which were later published in some of Pennant's zoological books.

[17] Together with a fellow artist, Peter Paillou, Parkinson worked for Banks on the latter's collections from his 1766 voyage to Newfoundland and Labrador.

[19] When Banks planned a voyage to Sweden in order to meet Linnaeus in Uppsala and to see Lapland, he intended to take Parkinson as his draughtsman.

The great Florilegium of his work was finally published in 1988 by Alecto Historical Editions in 35 volumes and has since been digitized by the Natural History Museum in London.