Education and marriage
The son of a prosperous lawyer, Stevens attended Harvard as a non-degree special student, after which he moved to New York City and briefly worked as a journalist. He then attended New York Law School, graduating in 1903. On a trip back to Reading in 1904 Stevens met Elsie Viola Kachel (1886–1963, also known as Elsie Moll), a young woman who had worked as a saleswoman, milliner, and stenographer. After a long courtship, he married her in 1909 over the objections of his parents, who considered her lower-class. As The New York Times reported in an article in 2009, "Nobody from his family attended the wedding, and Stevens never again visited or spoke to his parents during his father’s lifetime."  A daughter, Holly, was born in 1924. She later edited her father's letters and a collection of his poems.
In 1913, the Stevenses rented a New York City apartment from sculptor Adolph A. Weinman, who made a bust of Elsie. Her striking profile was later used on Weinman's 1916-1945 Mercury dime design and possibly for the head of the Walking Liberty Half Dollar. In later years Elsie Stevens began to exhibit symptoms of mental illness and the marriage suffered as a result, but the Stevenses remained married.
After working for several New York law firms from 1904 to 1907, he was hired on January 13, 1908, as a lawyer for the American Bonding Company. By 1914 he had become the vice-president of the New York office of the Equitable Surety Company of St. Louis, Missouri.
When this job was abolished as a result of mergers in 1916, he joined the home office of Hartford Accident and Indemnity Company and left New York City to live in Hartford, where he would remain the rest of his life. His first residence was located at 594 Prospect Avenue, but he remained there for only one year. In 1917 Stevens and his wife moved to 210 Farmington Avenue where they remained for the next seven years and where he completed his first book of poems, Harmonium. From 1924 to 1932 he resided at 735 Farmington Avenue. In 1932 he purchased a 1920s Colonial at 118 Westerly Terrace where he resided for the remainder of his life.
By 1934, he had been named vice-president of the company. After he won the Pulitzer Prize in 1955, he was offered a faculty position at Harvard but declined since it would have required him to give up his vice-presidency of The Hartford.
From 1922 to 1940, Stevens made numerous visits to Key West, Florida, where he generally lodged at the Casa Marina, a hotel on the Atlantic Ocean. He first visited in January 1922, while on a business trip. "The place is a paradise," he wrote to Elsie, "midsummer weather, the sky brilliantly clear and intensely blue, the sea blue and green beyond what you have ever seen." The influence of Key West upon Stevens's poetry is evident in many of the poems published in his first two collections, Harmonium and Ideas of Order. In February 1935, Stevens encountered the poet Robert Frost at the Casa Marina. The two men argued, and Frost reported that Stevens had been drunk and acted inappropriately. The following year, Stevens allegedly assaulted Ernest Hemingway at a party at the Waddell Avenue home of a mutual acquaintance in Key West. Stevens broke his hand, apparently from hitting Hemingway's jaw, and was repeatedly knocked to the street by Hemingway. Stevens later apologized. In 1940, Stevens made his final trip to Key West. Frost was at the Casa Marina again, and again the two men argued.
Last Illness and Death
On March 28 1955 Stevens first went to see Dr. James Moher. Dr. Moher's examination did not reveal anything and ordered Stevens to undergo an x-ray and barium enema on April 1, neither of which showed anything. On April 19 Stevens underwent a G.I. series that revealed diverticulitis, a gallstone, and a severely bloated stomach. Stevens was admitted to St. Francis Hospital and on April 26 he was operated on by Dr. Benedict Landry. It was determined that Stevens was suffering from stomach cancer. Stevens was released on May 11 and returned to his home on Westerly Terrace to recuperate. His wife insisted on trying to attend to him as he recovered but she had suffered a stroke in the previous winter and she was not able to assist as she had hoped. Stevens entered the Avery Convalescent Hospital on May 20. By early June he had recovered some of his strength and on June 9 he attended a ceremony at the University of Hartford where he received an honorary Doctor of Humanities degree from the Hartt College of Music. On June 13 he traveled to New Haven to receive an honorary Doctor of Letters degree from Yale University. On June 20 he returned to his home at Westerly Terrace and also insisted on returning to work. On July 21 Stevens was readmitted to St. Francis Hospital and his condition deteriorated. On August 1 he lapsed into a coma and died on August 2 1955 at eight-thirty in the morning.
Stevens may have been baptized a Catholic in April 1955 by Fr. Arthur Hanley, chaplain of St. Francis Hospital in Hartford, Connecticut, where Stevens spent his last days suffering from stomach cancer. This purported deathbed conversion is disputed, particularly by Stevens's daughter, Holly. There is no official record of Stevens's "baptism." After a brief release from the hospital, Stevens was readmitted and died on August 2, 1955, at the age of 75. He is buried in Hartford's Cedar Hill Cemetery.
Stevens was politically conservative and described by the critic William York Tindall as a Republican in the mould of Robert A. Taft.