Cleveland Salter Rockwell was born in 1837 in Youngstown, Ohio, the son of a lawyer who was involved with the Cleveland and Pittsburgh Railroad. After the death of Rockwell's mother, the family moved to Cleveland, Ohio. Rockwell attended secondary school in Troy, New York, and later became a student at New York University. In 1856, he was appointed to the U.S. Coast Survey, and was then assigned to survey a section of the New York harbor. From 1858 to 1861, his primary work was surveying the South Carolina and Georgia coasts in the area from St. Helena Sound, South Carolina to Savannah, Georgia. During the Civil War, the Coast Survey's activities supported the operations of the Union Army. Rockwell, who was commissioned as a captain of engineers in December 1863, performed additional work in South Carolina and Georgia, as well as surveys in Virginia; North Carolina; Maine; the area of Philadelphia, Pennysylvania; the area of Knoxville, Tennessee; and New York.
After the war, he worked with other U.S. engineers in Colombia, in response to a request from Colombia's president for aid from the Coast Survey, and subsequently worked on surveys in Maine and Georgia.

In 1867, Rockwell was promoted to the post of assistant in the Coast Survey and transferred to San Francisco, California. He surveyed the area around San Francisco and then went north in 1868 to survey the entrance to the Columbia River. For a period of years, he alternated between work in California and in the Pacific Northwest. In 1869, Rockwell married Cornelia Fleming Russell (1856-1922), who was born in Tennessee. In the late 1870s, the Rockwells moved from San Francisco to Albina, Oregon (later part of Portland). Cleveland Rockwell subsequently worked in various parts of Oregon, surveyed the Willamette River, and traveled to Alaska and British Columbia. In the early 1880s, Cleveland and Cornelia Rockwell had two daughters, their only children who lived to adulthood: Gertrude Ellinor Rockwell (later Mullay, 1881-1936), and Cornelia Rockwell (later Cornelia Stephens, then Cornelia Rockwell Kearney, 1882-1949). In the late 1880s, Cleveland Rockwell conducted a survey of a section of the Oregon coast, and after additional work in California and on the Columbia River, he retired to Portland in 1892. Also in that year, the Rockwell family took a vacation trip, visiting the Puget Sound region in Washington state, British Columbia, and Alaska.

Throughout Rockwell's years with the Coast Survey and after, he sketched and painted, and his work was exhibited in San Francisco, California and in Portland, Oregon. He was an organizer of the Portland Art Club in 1885, and served as president of the Oregon Art Association in 1896. Cornelia F. Rockwell also made art, and accompanied Cleveland Rockwell on field outings in which they made sketches and watercolors of wildflowers in the Pacific Northwest and California. Toward the end of Rockwell's life, he worked as a civil engineer, was active in local banking and in Republican party politics, and contributed articles to Pacific Monthly and West Shore. His drawings were used in the decoration of the battleship Oregon's silver punch set in 1897. Rockwell died in Portland in 1907.