Irish landscape artist, genre painter and illustrator William John Hennessy was born in County Kilkenny but soon joined his father John Hennessy in Canada whence he had fled from the British authorities following his involvement with the Young Ireland movement of 1848. Moving with his parents to New York, the young William Hennessy began drawing while still in his early teens, and at 15 attended the National Academy of Design to study fine art painting. In 1857, he first showed at the National Academy in New York (NA), to which he was elected as a full member in 1863. The luminous quality of his landscape painting as well as the sentimental appeal of his genre painting won him considerable praise from art critics. 

Hennessy was also a fine illustrator, receiving commissions to illustrate the works of American poets such as Tennyson, Longfellow and Whittier. Co-founder of the Artists’ Fund Society, he became an honorary member of the American Society of Painters in Watercolours. In 1870, he moved to London. Between 1871 and 1882 he showed at the Grosvenor Gallery, New Gallery and the Royal Academy (RA). In addition, he exhibited his work at Liverpool’s Walker Art Gallery, Manchester City Art Gallery and the Glasgow Institute of the Fine Arts. In 1902 Hennessy became a member of the Royal Institute of Oil Painters. Meanwhile, during the period 1879-1907 he submitted eight paintings to the Royal Hibernian Academy (RHA) in Dublin.

After moving to London William Hennessy spent the summer months in Normandy, where he painted a number of rural-scenes and landscapes

William Hennessy's pictures are represented in many public and private collections, including: Amhurst College, Massachusetts; Ulster Museum, Belfast; Museum and Art Gallery, Brighton; Yale University, Connecticut; Brooklyn Museum, New York; National Academy of Design, New York; Vassar College, New York; and others.

Joseph William Comyns Carr (1 March 1849 – 12 December 1916) was an English drama and art critic, gallery director, author, poet, playwright and theatre manager. Beginning his career as an art critic, Carr was a vigorous advocate for Pre-Raphaelite art and a vocal critic of the "short-sighted" art establishment.

Mr. Hennessy's "Summer Evning on the Thmes" was engraved in L'Art, October 6, 1878, and Mr. J. Comyns Carr wrote of it in that journal:

"A simple and large style brings out marvelously well the simplicity of the subject. Hitherto, Mr. Hennessy has shown a tendency to exagerate the opalescent hues of twilight, at the risk of imparting a twinkling glitter to the most delicate gradations of light. This habit he has conquered and the success of his recent efforts proves, to hios honor, that it was carelessness of custom rather than a willful mistake. This view on the river, with its heavily laden barges floating softly down the stream, is distinguished not only by truth of general effect, but also by that accuracy in the observation of details which alone can fix an impression and stamp its real character on the scene selected for painting"