Tom Jones, a "bastard" raised by the philanthropic Allworthy, is the novel's eponymous hero and protagonist. Although Tom's faults (namely, his imprudence and his lack of chastity) prevent him from being a perfect hero, his good heart and generosity make him Fielding's avatar of Virtue, along with Allworthy. Tom's handsome face and gallantry win him the love and affection of women throughout the countryside. His dignified, though natural air induces characters to assume that he is a gentleman—which ultimately turns out to be true.
Sophia Western is Fielding's beautiful, generous heroine and the daughter of the violent Squire Western. Like Tom, Sophia lavishes gifts on the poor, and she treats people of all classes with such respect that one landlady cannot believe she is a "gentlewoman." Sophia manages to reconcile her love for Tom, her filial duty to her father, and her hatred for Blifil through her courage and patience. Sophia's natural courtesy can be contrasted with her Aunt Western's artificial manners.
Mr. Allworthy is just what his name implies - all worthy. Allworthy has a reputation throughout England because of his benevolent, altruistic behavior. The moral yardstick of the novel, Allworthy's only fault (which ironically propels much of the plot) is that—due to his goodness—he cannot perceive the evil in others.
Blifil is antagonist to Tom Jones and the son of Bridget Allworthy and Captain Blifil. Although he appears at first to be a virtuous character, his hypocrisy soon exposes itself—Blifil pretends to be pious and principled, but greed governs him. The fact that Blifil has few redeeming qualities makes Tom compassion for him at the end of the novel—after the revelation that Blifil kept the secret of Tom's birth to himself—even more commendable. Blifil's dearth of natural human appetites—he at first does not desire Sophia—does not distinguish him as a virtuous character, but rather provides a depressing picture of what humanity would be like if devoid of passion.
Squire Western is a caricature of the rough-and-ready, conservative country gentleman. Affectionate at heart, the Squire nevertheless acts with extreme violence towards his daughter Sophia, by constantly incarcerating her, and even verbally and physically abusing her. However, since the Squire is a caricature, Fielding does not intend for us to judge these actions too harshly. Similarly, the Squire's insistence on Sophia marrying Blifil has less to do with greed than with his stubbornness and adherence to tradition. Squire Western's speaks in West Country dialect, and peppers his speech with curses.
Mrs. Western, the foil of her brother Squire Western, is a caricature of the artificial city lady who always acts out of expediency. Mrs. Western prides herself on being adept at all intellectual pursuits—from politics to philosophy to feminism to amour—yet her ignorance reveals itself on numerous occasions (she thinks that Socrates lectured to students instead of engaging in conversational debate). Mrs. Western's sole aim in the novel is to improve the Western name by marrying off Sophia to the richest, most prosperous man she can find.
Partridge is the teacher whom Allworthy accuses of being Tom's father. He is a kind of comedic Harlequin character (Fielding even compares him to Harlequin). Although pathetic, bumbling, and cowardly, Partridge remains a loyal servant to Jones and deserves his reward at the end of the novel. Partridge has a passion for speaking in Latin non sequiturs. Although Partridge creates problems for Tom and Sophia by boosting Tom's reputation and defiling Sophia's to all and sundry, Tom cannot help forgiving Partridge, who always has the best of intentions.
Jenny Jones (Mrs. Waters) is the student of Partridge whom Allworthy banishes for being Tom's mother—at the end of the novel we learn that Jenny is not Tom's mother. Jenny reappears as "Mrs. Waters" at Upton, where Tom saves her from a robbery. Although Jenny does not possess the beauty of a Sophia, her very white breasts attract Tom to her. Although she protests to Mr. Allworthy at the end of the novel that she has led a virtuous life, her seduction of Tom in Upton suggests otherwise. She eventually marries Parson Supple, a friend of Western.
Bridget Allworthy is the mother of Blifil and Tom. An unattractive lady who resents beautiful women, Bridget marries Captain Blifil because he flatters her religious views. Although Bridget's affection wavers between Blifil and Tom as the boys mature, she becomes devoted to Tom before her death—largely due to his good looks and gallantry.
Lady Bellaston is a London lady, and a relative of Sophia, whose passionate, lusty personality leads her to dabble in intrigues. The stem of her last name "Bella-", meaning "war" in Latin, points to her malicious nature—she thinks of no one but herself. Lady Bellaston carries out a vengeful battle against Tom and Sophia with the utmost glee.
Harriet Fitzpatrick is Sophia's cousin and the wife of Mr. Fitzpatrick. Pretty and charming, she is nevertheless selfish and contrives against Sophia in order to improve her relationship with Squire Western and Mrs. Western.
Mr. Fitzpatrick is a rash Irishman whom Harriet Fitzpatrick casts in the light of an ogre chasing her across the countryside. Fitzpatrick becomes admirable, however, when he admits to initiating the duel with Tom at the end of the novel.
Mr. Dowling is a shrewd, shifty lawyer who becomes a friend of Blifil. Always operating out of expediency, when Dowling realizes that Blifil will not be able to reward him for his efforts, he defects to Tom and Allworthy's side.
Mrs. Miller is a faithful friend to Tom and the most caring and concerned of mothers to Nancy and Betty. Feisty and active, Mrs. Miller carries through on her promises and becomes Tom's biggest advocate to Allworthy. She is trusting and loyal.
Nightingale, although a foppish city gentleman, possesses the laudable traits of loyalty and compassion—although not always in affairs of love. It takes a little time for Tom to convince Nightingale not to abandon Nancy, since Nightingale is caught up in his image in London. To his credit, Nightingale transforms and follows Tom's principles of Honour—that is, fulfilling verbal commitments.
Lord Fellamar is a suitor of Sophia who, though he has a conscience, easily allows himself to be manipulated by Lady Bellaston.
Square is a philosopher who lives with Allworthy. He justifies his questionable behavior (such as making love to Molly Seagrim) by contorting his philosophical notions. Square, although a foil to Thwackum, is less sinister than the latter. Indeed, Square's virtuous transformation at the end of the novel allows Allworthy to forgive Tom.
Thwackum is the vicious tutor of Blifil and Tom who constantly beats Tom and praises Blifil. Thwackum, who claims to value Religion above all else, seeks only his own good.
Molly Seagrim is the rugged, unfeminine daughter of Black George who seduces Tom. Feisty and aggressive, Molly enjoys the company of men, and fights fiercely for her rights.
Black George is the servant who is favored by Tom. Although of dubious moral tincture (Black George steals and lies), Black George's loyalty to and love of Tom nevertheless emerges.
Nancy Miller is the daughter of Mrs. Miller who becomes Nightingale's wife.
The ironic, intrusive narrator can be assumed to be Fielding himself since he reflects on his process of creating Tom Jones.