Early life and work Steinbeck was born to John Steinbeck (a first-generation American of German descent, whose family name was originally Grossteinbeck), and Olive Steinbeck (née Hamilton) (also a first-generation American, but of Scots-Irish descent) in Salinas, California. He had three (3) sisters: two older and one younger. Steinbeck's father worked in county government as a treasurer, and Steinbeck's mother was a teacher.

Steinbeck enrolled in Stanford University in 1919 and attended until 1925, but dropped out and moved to New York City where he labored at various jobs - including construction work - while developing his skills as a freelance writer. He was unable to find a publisher, and returned back to California.

Steinbeck's first novel, published in 1929, was the unsuccessful mythological Cup of Gold. He married Carol Henning in 1930 and while he continued to write, he also cared for his ailing parents—his mother died in 1934, and his father in 1935. Steinbeck achieved his first critical success with the novel Tortilla Flat, which won the California Commonwealth Club's Gold Medal. The story of the adventures of young men in Monterey during the Great Depression was made into a film of the same name in 1942, starring Spencer Tracy, Hedy Lamarr, and John Garfield.

Political views increasingly influenced Steinbeck's writing. Carol Henning was a Marxist who took him to radical political meetings in San Francisco and the couple visited the Soviet Union in 1937, a common voyage of American liberal intellectuals hoping to view the successes of the world's foremost communist power. She registered as a member of the United States Communist Party, reportedly over Steinbeck's objections.

Marriages and children Steinbeck and Henning separated in 1941 and Steinbeck moved to New York with Gwyndolyn Conger. His divorce from Henning was finalized in 1942. In 1943 he married Conger, and the couple had two sons: Thomas "Thom" Steinbeck who was born August 2, 1944, and John Steinbeck IV who was born June 12, 1946. Conger and Steinbeck divorced in 1949.

Thomas Steinbeck is a fiction writer who lives on the Central Coast of California and who has published a collection of stories, Down to a Soundless Sea (2003, ISBN 0345455770) as well as numerous screenplays.

Steinbeck's second son John Steinbeck IV (June 12, 1946 - February 7, 1991) shared an Emmy Award in 1967-1968 for his work in Vietnam on the documentary film "Charlie Company". During his lifetime, he published one book, In Touch. He was haunted by a life-long battle with alcoholism and drug addiction, but was sober for the last three years of his life. John Steinbeck IV died in San Diego, California on February 7, 1991 after complications resulting from back surgery at the age of 44. His former wife, Nancy, published his posthumous memoirs in a book called The Other Side of Eden in 2001. The story follows the journey through John's trials and tribulations as the child of a famous father, his experiences in Vietnam as a soldier and journalist, and his battle with addiction, as she weaves the story of their love affair amongst his writing. Publisher's Weekly says "This is a powerful account of healing and liberation. This book will help many people."

Actress Ava Gardner introduced Steinbeck to Elaine Anderson Scott at a dinner party, and John married Elaine in December of 1950 within a week after her divorce from actor Zachary Scott became final. Elaine survived John.

Critical success Back in California, Steinbeck found his stride in writing "California novels" and Dust Bowl fiction, set among common people in the Great Depression. His socially-conscious novels about the struggles of rural workers achieved major critical success. Of Mice and Men, his novella about the dreams of a pair of migrant laborers working the California soil, was critically acclaimed. Broadway producer Sam H. Harris approached Steinbeck to adapt his own novella as a stage play, although Steinbeck had no previous experience as a playwright, and did not consider himself up to the task. Harris also engaged veteran director George S. Kaufman to direct the play, as yet unwritten. It was Kaufman who guided and encouraged Steinbeck all through the process of adapting his novella for the stage. Because Steinbeck would ultimately write only two stage plays (his second was an adaptation of The Moon Is Down), and because Kaufman was an experienced playwright, it is often assumed that Kaufman was Steinbeck's uncredited co-author. However, correspondence between Steinbeck and Kaufman verifies that the revisions were entirely done by Steinbeck.

The stage adaptation was a smash hit, starring Broderick Crawford as the dim-witted but physically powerful itinerant farmhand "Lennie" and Wallace Ford as his cousin and companion "George". However, Steinbeck refused to travel from his home in California to attend any performance of the play during its New York run, telling Kaufman that the play as it existed in his own mind was "perfect", and that anything presented onstage would inevitably be a disappointment.

The play was rapidly adapted into a 1939 Hollywood film, in which Lon Chaney Jr. gave a standout performance as "Lennie" (he had already portrayed this role in the Los Angeles production of the play) and Burgess Meredith was cast as "George." Steinbeck followed this wave of success with The Grapes of Wrath, (1939), based on newspaper articles he had written in San Francisco, and considered by many to be his finest work. The novel won the Pulitzer Prize for the Novel in 1940 even as it was made into a famous film version starring Henry Fonda and directed by John Ford.

The success of The Grapes of Wrath, however, was not free of controversy, as Steinbeck's liberal political views, portrayal of the ugly side of capitalism, and mythical reinterpretation of the historical events of the Dust Bowl migrations led to backlash against the author, especially close to home. Of the controversy, Steinbeck himself wrote, "The vilification of me out here from the large landowners and bankers is pretty bad. The latest is a rumor started by them that the Okies hate me and have threatened to kill me for lying about them. I'm frightened at the rolling might of this damned thing, It is completely out of hand ; I mean a kind of hysteria about the book is growing that is not healthy."

The film versions of The Grapes of Wrath and Of Mice and Men (by two different movie studios) were in production simultaneously, and Steinbeck had the immensely satisfying experience of spending a full day on the set of The Grapes of Wrath, then spending the next day on the set of Of Mice and Men.

1940s-1960s In 1940, Steinbeck's interest in marine biology and his friendship with Ed Ricketts led him to voyage in the Gulf of California, also known as the "Sea of Cortez," where they collected biological specimens. Their account of this trip was later published as The Log from the Sea of Cortez, and describes the daily experiences of the trip as well.

During the Second World War, Steinbeck served as a war correspondent for the New York Herald Tribune.

He continued to work in film, writing Alfred Hitchcock's Lifeboat (1944), and the film A Medal for Benny (1945), about paisanos from Tortilla Flat going to war.

His novel The Moon is Down (1942), about the Socrates-inspired spirit of resistance in a Nazi-occupied village in northern Europe, was made into a film almost immediately. It is presumed that the country in question was Norway, and in 1945 Steinbeck received the Haakon VII Medal of freedom for his literary contributions to the Norwegian resistance movement.

After the war, he wrote The Pearl (1947), already knowing it would be filmed., and traveled to Mexico for the filming; on this trip he would be inspired by the story of Emiliano Zapata, and wrote a film script that was directed by Elia Kazan and starred Marlon Brando and Anthony Quinn.

In 1948 Steinbeck again toured the Soviet Union, together with renowned photographer Robert Capa. In the same year he was also elected to the American Academy of Arts and Letters.

Following his divorce of Gwyndolyn Conger, Steinbeck wrote one of his most popular novels, East of Eden(1952).

Following the success of Viva Zapata!, Steinbeck collaborated with Kazan on the theatrical production of East of Eden, James Dean's film debut.

Steinbeck was a friend to Presidents John F. Kennedy and Lyndon B. Johnson.

In 1962, Steinbeck won the Nobel Prize for Literature for his “realistic and imaginative writing, combining as it does sympathetic humor and keen social perception.” In his acceptance speech, he said,

"the writer is delegated to declare and to celebrate man's proven capacity for greatness of heart and spirit - for gallantry in defeat, for courage, compassion and love. In the endless war against weakness and despair, these are the bright rally flags of hope and of emulation. I hold that a writer who does not passionately believe in the perfectibility of man has no dedication nor any membership in literature."