Robert Newton Peck, the son of Haven and Lucile (Dornburgh) Peck, was born on February 17, 1928, in a rural Shaker community in Vermont. He h as been a farmer, a lumberjack, a hog butcher, and a paper mill worker. From 1945-1947 he served in the army and was stationed in Italy, Germany, and France. After returning to the U.S., he attended Rollins College in Winter Park, Florida, and received his bachelor's degree in 1953. He married Dorothy Houston, a librarian, in 1958. The Pecks have two children. Peck's first book, A Day No Pigs Would Die (1972), launched his prolific writing career. The book is based on Peck's own boyhood in rural Vermont and his relationship with his father. The importance of a parental bond occurs in several of Peck's books.

Peck says he writes for no certain age level, and most of his books cross the lines between adult, young adult, and children's literature. Many of his works are set in rural Vermont in the 1920s and 1930s or, in the case of his historical novels, in the Revolutionary War period. Early twentieth-century Florida is the setting for several of his later works.

In 1974 his series of Soup books was begun with the publication of Soup. A childhood friend of Peck's inspired these books about the misadventures of two best friends. His Soup for President won the 1982 Mark Twain Award. Another series for the same third to sixth grade readers started with the 1977 publication of Trig, the story of a tomboy. Peck publishes an average of three books a year. Having written two books on the craft of writing for adults, he is in demand as a speaker at writing workshops and seminars, yet he also takes time to answer his fan mail. His hobbies include playing ragtime piano, writing songs, and skiing.