Marriott was born at Marriott Settlement near Ogden, Utah, and was raised on his father's farm. His father gave him considerable responsibility at an early age: he was sent to San Francisco on his own with 3,000 sheep in a railcar at the age of 14.

At the age of 19 and as a devout Mormon, he undertook the traditional missionary work of the church for two years, being assigned to New England. On his way home after completing his mission, he passed through Washington D.C. during the sweltering summer months of 1921. While there:

Marriott was a brother of the Phi Delta Theta Fraternity at the University of Utah and of Alpha Kappa Psi, his son J. W. "Bill" Marriott, Jr. was a member of Sigma Chi. After graduating from Weber College and later, the University of Utah in 1925, Marriott remembered his experience in Washington, D.C. and decided to look into a venture there.

In 1927, he secured from A&W Root Beer the franchise rights for Washington, D.C.; Baltimore, Maryland; and Richmond, Virginia; he then moved to Washington to open a nine-stool root beer stand there with his business partner, Hugh Colton. They opened on May 20, 1927 at 3128 14th Street, NW. He returned to Utah two weeks later, and married Alice Sheets on 9 June 1927. With the approach of cooler Autumn months, and with the addition of Mexican food items to the menu, the stand became The Hot Shoppe, a popular family restaurant. In 1928, he opened the first drive-in east of the Mississippi, and the business was incorporated as Hot Shoppes, Inc. in Delaware in 1929. During the Second World War, the business expanded to include the management of food services in defense plants and government buildings, such as the U.S. Treasury.

In 1935 he was diagnosed as having malignant cancer of the lymph nodes, and given between six months and a year to live. However, he survived and lived another half century.

Marriott's restaurant chain grew, and the company went public in 1953. In 1957, he expanded his business to hotels, opening the first Marriott hotel—actually a motel, the Twin Bridges Motor Hotel in Arlington, Virginia. The company became Marriott, Inc., in 1967. Two large chains were added to the group, the Big Boy family restaurants in 1967 and Roy Rogers Family Restaurants in 1968.

Over the years, Marriott's company interests expanded. Continuing with food services, Marriott eventually invented airline in-flight food service. This segment of their enterprise continues to be a large part of their business, providing food services to many major airlines. Marriott also provides food services to many colleges, elementary schools and other venues.

Marriott was an energetic worker and rarely rested, preferring to run his company. Many attested to the fact that he ate, lived, breathed and dreamed about how to run and improve his company:

Even after the company grew to include hundreds of restaurants and hotels, Marriott vowed to personally inspect every establishment at least four times a year.

Marriott tempered his rigid demands for perfection with devotion to his employees. According to his son, Bill Jr.,: