Lockwood de Forest was born in New York in 1850 to a prominent family. He grew up in Greenwich Village and on Long Island at the family summer estate in Cold Spring Harbor. As was customary for a cultivated family in the Gilded Age, the de Forests made frequent trips abroad. Excursions to the great museums, which were prominent on the de Forests agenda, deepened the young Lockwood's familiarity with European painting and sculpture. Though he had begun drawing and painting somewhat earlier, it was during a visit to Rome in 1868 that nineteen-year-old de Forest first began to study art seriously, taking painting lessons from the Italian landscapist Hermann David Salomon Corrodi (1844–1905). More importantly, on the same trip, Lockwood met one of America’s most celebrated painters, (and his maternal great-uncle by marriage) Frederic Edwin Church (1826–1900), who quickly became his mentor. De Forest accompanied Church on sketching trips around Italy and continued this practice when they both returned to America in 1869. Early on in his career, de Forest made a habit of recording the date and often the place of his oil sketches, as to create a visual diary of his travels. Lockwood’s profession as a landscape painter can be primarily attributed to Frederic E. Church and his belief in the young artist’s talent.
De Forest often visited Church in the Hudson River community of Catskill where, in addition to sketching trips and afternoons of painting, he assisted with the architectural drawings and planning of Olana. In 1872, de Forest took a studio at the Tenth Street Studio Building in New York. During these formative years de Forest counted among his friend’s artists such as Sanford Robinson Gifford (1823–80), George Henry Yewell (1830–1923), John Frederick Kensett (1816–72), Jervis McEntee (1828–91), and Walter Launt Palmer (1854–1932).
Over the next decade de Forest experienced success as a painter. He exhibited for the first time at the National Academy of Design in 1872, and made two more painting trips abroad, in 1875–76 and 1877–78, traveling to the major continental capitals but also the Middle East and North Africa. His trip to the Middle East and the library at Church’s home, Olana, established his interest in design during his mid-twenties. From about 1878 to 1902, landscape painting was overshadowed by his activities and preoccupation with East Indian architecture and décor, a style that became quite fashionable in late nineteenth century America. From 1879-1883, de Forest founded Associated Artists along with Louis Comfort Tiffany, Candace Wheeler and Samuel Colman. Besides being patronized by the most prominent families in America, Associated Artists was commissioned to redecorate the White House in 1882.
While working in the decorating business, De Forest had continued to paint at home and wherever he traveled. He exhibited his work frequently at the Century Club and the National Academy of Design. In 1898, de Forest was made a full member of the Academy. After spending many winters in Santa Barbara, California around 1889, de Forest built a house and moved there permanently in 1922. De Forest created hundreds of oil sketches of Californian sites and also traveled to the Pacific Northwest (1903), Maine (1905 and 1908), the Grand Canyon (1906 and 1909), Mexico (1904, 1906–7 and 1911), Massachusetts (1910), and Alaska (1912). Lockwood de Forest died in Santa Barbara in 1932.