Clark always credited her parents with instilling her with a sense of strength and patience. Her father, Peter Poinsette, had been born on the plantation owned by Joel Poinsette (a botanist and former ambassador to Mexico who brought back the flaming red flower that bears his name). When he was freed at the end of the Civil War, he met and married Victoria Anderson, a striking and sharp woman who had been educated in a rigorous European-style school in Haiti, where some of her family lived. The Poinsettes were strict and involved parents who insisted that Clark and her seven brothers and sisters apply themselves to their studies rigorously.
Clark later recalled that a turning point in her life came when a teacher recognized the merit of her work. "She praised me for [my paper] before the class. This sudden recognition did something for me," she said. "From then on, I felt better about going to public school." Although Clark's teachers sensed her intellect early on and urged her to go on to college, she knew her parents could not afford it. Thus, she resolved to find work as a teacher and attend summer school to get a degree. (Eventually, she received her bachelor's degree from Benedict College in 1942 and her master's degree from Hampton Institute in 1955.)
Because the Charleston public schools did not hire black teachers, even in the designated black schools, Clark had to look elsewhere for work. In 1916, she found a one room schoolhouse on John's Island, a piece of lush land off the coast of South Carolina that was overwhelmingly African-American and isolated enough that the local residents communicated in "Gullah," a dialect that fused English with various African languages.
Although the conditions were spare and she had to create her own materials, Clark loved teaching. Soon, she was running classes for adults as well as children, teaching literacy and a sort of civics curriculum that was an early model of her political leadership in years to come.