Casimir Griswold was the youngest of five sons of a father who was, Henry Tuckerman wrote, "of a literary turn"; he edited and published several of Ohio's earliest newspapers. Tuckerman also recounted that all five brothers demonstrated artistic talent, but only one besides Casimir took up art seriously. It was this older brother who gave him basic instruction and encouraged him to go to Cincinnati, in about 1850, to work for and learn from a wood engraver. He arrived in New York with his employer, again according to Tuckerman, in the autumn of 1850.
Griswold debuted as a painter in the 1857 Academy annual exhibition with two works, a landscape lent by its owner and View on Salt Lick Run, Va.; this suggests that he had already attracted some patronage and had done some traveling. Academy annuals would continue to be Griswold's principal venue for nearly two decades. He rarely missed showing-usually two or three paintings each year-through 1874. A founder in 1859 of the Artists' Fund Society of New York, he also contributed consistently to the society's exhibitions from 1860 through 1874. He enrolled in the Academy school's life class for the 1860-61 season. For at least part of 1861 Griswold lived in Brooklyn, and during the 1860s he frequently contributed to exhibitions of the Brooklyn Art Association.
Few of Griswold's works are now located, but something of the character of his landscapes, and his favored sites, may be determined from the titles of his exhibition pieces. His scenes were identified as being in Ulster and Rockland counties and on Long Island in New York and, occasionally, in Connecticut. From 1868, Newport, Rhode Island, was a frequent source of subjects. Many of his paintings are identified with the months and seasons, suggesting a preoccupation with climatic and atmospheric effects. A number of his works also bore such titles as Study from Nature, Study of Weeds, and Study in the Woods, probably reflecting his association with the American Pre-Raphaelite movement.
Beginning in the late 1850s, and largely in response to the writings of John Ruskin, a small group of artists began diligently pursuing an approach to painting that demanded intense study of nature-especially in isolated, closely viewed segments-and an equally meticulous style of rendering. The high point of the movement came with the founding in January 1863 of the Association for the Advancement of Truth in Art, dedicated to the reform of American art and architecture, and the publication of a periodical, New Path, which promoted its principles. The rigorous demands-both intellectual and technical-of this aesthetic had fairly exhausted its painter-adherents within about two years, and gradually they relaxed their attitudes and painting styles to accommodate the needs of earning a living. Although never part of the group's inner circle, Griswold was one of its participants.
By January 1872, Griswold was living and working in Rome, his trip there having been financed by his friend Elihu Vedder. When he next contributed to an Academy annual, in 1874, he showed a view of Lake Nemi and gave his address as Rome. He is known to have been in Rome from 1880 to 1886, but it seems likely that he spent the entire period 1872-86 there. His work was not seen in an Academy annual again until 1887 (at which time he again gave a New York address); he rarely contributed to any American exhibitions between 1874 and 1887, and such works as were shown were all of Italian subjects.
For most of the remainder of his long career, Griswold continued to be a regular Academy exhibitor, making his last appearance in the 1905 annual. He had a variety of New York addresses throughout this period, except during 1898, when he lived in Newtown, Connecticut; in 1900, he gave his address as "care of" the New York studio of George Randolph Barse, Jr., an Academician who was more than twenty-five years Griswold's junior. The titles of the paintings he showed in these years echo those of the 1860s and 1870s, suggesting that he was not keeping pace with a younger generation.