Martin (Grandpa) Vanderhoff: Thirty-five years ago Grandpa walked away from a successful business career in order to be able to do whatever he wanted, whenever he wanted. Clearly the patriarch of his clan, Grandpa has imparted this infectious philosophy of personal happiness above all else, not only to his own progeny, but also to numerous others, such as Mr. De Pinna, who have happened to cross his path.
Penelope (Penny) Sycamore: Grandpa’s daughter, and heir to his ideal of carefree happiness, Penny spends much of her time writing plays, because a typewriter was delivered to the house by accident eight years previously.
Paul Sycamore: Penny’s husband, Paul apparently gave up a planned career as an architect to buy into Grandpa’s way of life. Paul’s major activities include making fireworks and building meccano models.
Essie Carmichael: Penny and Paul’s daughter, Essie has spent the last eight years studying ballet with Kolenkhov, apparently without displaying any talent or attaining any level of proficiency. Her only source of income is making and distributing homemade candy. She and her husband Ed are considering having a baby, pending Grandpa’s approval.
Ed Carmichael: Essie’s husband, Ed helps Essie distribute candy, prints various circulars on his printing press, and plays the xylophone.
Alice Sycamore: Penny and Paul’s daughter, Alice is the only member of the family to be gainfully employed outside the house and in regular contact with outside society, working for Mr. Kirby at Kirby & Co. Although she loves her family dearly, she is also sometimes frustrated or embarrassed by their absent-mindedness and unconventionality.
Anthony (Tony) Kirby, Jr.: The son of Mr. and Mrs. Kirby, Tony is the Vice President of Kirby & Co., a position that he has only held for a short while, as he is young and a recent college graduate. Madly in love with Alice, he clearly chafes against the boredom of the life his father has scripted for him.
Anthony Kirby, Sr.: Mr. Kirby runs a successful business on Wall Street. Conservative in his views, and a member of numerous social clubs, Mr. Kirby values his position and his social status. As a young man, however, he had other dreams.
Miriam Kirby: Outwardly conservative like her husband, Mrs. Kirby also seems to conceal a discontent with the monotony of her life.
Rheba: The Vanderhoff family’s maid, most of the time Rheba is treated by them more as a member of the family or a trusted confidant than as a servant.
Donald: Rheba’s boyfriend, Donald is also an intimate member of the Vanderhoff family’s inner circle. Although he is on government relief, he also does odd jobs for the family.
Mr. De Pinna: Mr. De Pinna came to the Vanderhoff house eight years ago to deliver ice and has been there ever since. He assists Paul with his firework experiments and generally assists Grandpa and his family as needed.
Boris Kolenkhov: Essie’s ballet instructor and an intimate friend of Grandpa Vanderhoff, Kolenkhov still keeps in touch with friends in his native Russia. Through his friendships with displaced Russian nobility, he demonstrates his nostalgia for pre-Revolutionary czarist Russia.
Willie C. Henderson: A staunch government woman from the Internal Revenue Department, Henderson has been dispatched to collect twenty-four years worth of back income taxes from Grandpa Vanderhoff.
Grand Duchess Olga Katrina: The former Grand Duchess and cousin to the former Russian Czar, Olga Katrina now waits tables at Childs’ Restaurant in Times Square and reminisces with Kolenkhov about pre-Revolutionary Russia.
Gay Wellington: An actress whom Mrs. Sycamore meets on a bus and invites home to read one of her plays. She is an alcoholic, gets very drunk and passes out shortly after arriving at the Sycamore's home.