Bonanza 'un 4 sezonu NBC 'da dimanche 23 septembre 1962 'dan dimanche 26 mai 1963'a kadar yayınlandı. 34 bölümlerinden oluşuyor, ilkinin adı "The First Born" ve sonuncusunun adı "Little Man...Ten Feet Tall".
The show chronicles the weekly adventures of the Cartwright family, headed by the thrice-widowed patriarch Ben Cartwright. He had three sons, each by a different wife: the eldest was the urbane architect Adam who built the ranch house; the second was the warm and lovable giant Eric "Hoss"; and the youngest was the hotheaded and impetuous Joseph or "Little Joe". Via exposition and flashback episodes and each wife was accorded a different ethnicity. The family's cook was the Chinese immigrant Hop Sing.