Sewell authored Black Beauty to highlight the prevalent mistreatment of horses. She portrays horses that are well-cared-for as well as those that suffer abuse. The differences in the horses' personalities can be quite striking. Three types of cruelty are revealed: intentional cruelty, cruelty driven by fashion, and cruelty stemming from ignorance. On several occasions, innocent bystanders intervene to help an abused horse, underscoring the notion that preventing animal cruelty is a collective responsibility. Sewell is particularly horrified by the common use of a device called a bearing rein (or checkrein), which prevents horses from lowering their heads.

Black Beauty's primary equine companions are Ginger and Merrylegs. Ginger is a spirited horse whose training and disposition starkly contrast with Black Beauty's. She is bad-tempered mainly due to the mistreatment she endured when she was young, whereas Black Beauty is good-tempered because he received kind treatment in his early years. Despite her issues, Ginger eventually calms down during her stay at Birtwick Hall, thanks to the humane treatment she receives there. Merrylegs is a pony who, like Black Beauty, exemplifies the positive outcomes of compassionate care. Other notable horse characters include Sir Oliver, who had his tail docked as a colt, and Captain, a former cavalry horse.

The main human characters include Black Beauty's first owner, whose name remains undisclosed; his second owner, Squire Gordon of Birtwick Hall; John Manly and little Joe Green, the grooms at Birtwick Hall; and the cab driver Jerry Barker and his family. These kind and knowledgeable individuals strive to treat their horses well, and their horses reflect the benefits of their considerate care.

The cruel humans are minor characters, such as various carters who are reprimanded for deliberately mistreating their horses. Two more significant abusers are Samson Ryder, a horse trainer, and Nicholas Skinner, a cab owner. Ryder initially trained Ginger, contributing to her bad temper. Skinner eventually acquires Black Beauty and hires him out along with many exhausted, old horses at such high rates that cab drivers must overwork the horses to make a living. He never allows his horses a day off, stating, "My plan is to work 'em as long as they'll go, and then to sell 'em for what they'll fetch, at the knacker's or elsewhere."

Another theme in Black Beauty is the challenging life of a cab driver, particularly the hypocrisy of churchgoers who use cabs to get to church. When Black Beauty was written, many people believed in the importance of keeping the Sabbath, meaning no work on Sundays. Those who hired cabs to attend church were observing the Sabbath themselves, yet causing the cab drivers to break their own Sabbath. In what might have been a journal entry or an unfinished letter, Sewell recounted a conversation with a cab driver, which inspired her to highlight the issue of hypocrisy in Sabbath observance. She shared a story told by the cab driver about a friend whose churchgoing passengers were so overtly hypocritical that they handed the cab driver a tract on keeping the Sabbath as they exited his cab on their way to Sunday services.

Lady Anne

At Earlshall Park, Black Beauty serves as Lady Anne’s riding horse for a time, although she refers to him as Black Auster.

Dolly Barker

Dolly, the eight-year-old daughter of Jerry the cab driver, would bring meals to her father at the cab stand. She was a part of Beauty's life when Jerry owned him.

Harry Barker

Harry, Jerry's twelve-year-old son, played a crucial role in helping with the horses' care. His dedication was evident in his capable assistance.

Jeremiah Barker

Known as Jerry, Jeremiah Barker owned Beauty for three years. He was a kind and decent cab driver in London who believed neither he nor his horses should work seven days a week. Jerry exemplifies honesty and integrity within the working class, embodying Sewell's moral lessons. He finds fulfillment in a job well done and is always ready to help others. Devoted to his wife and children, Jerry avoids taverns, having been a teetotaler for ten years. When illness forces him to stop working as a cab driver, he sells Beauty to a trusted friend who he believes will treat the horse well.

Polly Barker

Polly, Jerry Barker’s wife, is a cheerful and kind woman who lovingly cares for those around her. Her former employer holds her in high regard, staying in touch over the years and offering Jerry a job and a home for the family when he can no longer run his cab business.

Mr. Barry

Mr. Barry becomes one of Black Beauty’s owners after the horse’s knees are damaged. Despite being a gentleman, Mr. Barry relies on grooms to care for Beauty. After dealing with two dishonest grooms, he decides to sell Beauty and give up owning a horse.

Black Beauty

Black Beauty, the narrator of the novel, is a “well-bred and well-born” striking black horse with one white foot and a white star on his forehead. The character may be inspired by Sewell’s brother’s elegant carriage horse, Black Bess or Bessie. Beauty is the son of a wise mare named Duchess and the grandson of a famous race winner. Following his mother’s advice to always be good-hearted and hardworking, Beauty experiences a range of good and bad owners and grooms, as well as both pleasant and harsh jobs during his life in Victorian England. Through Beauty and the other horses he encounters, readers learn about the mistreatment horses often face and the demanding nature of some of their work. Sewell uses Beauty to raise public awareness about the need for more humane treatment of horses and other animals.

Beauty starts life on a positive note under the expert care of Farmer Grey and then enjoys a happy period at Birtwick Park. His master at Birtwick Park is a knowledgeable advocate for the humane treatment of horses. However, when this master has to leave England, Beauty's life takes a turn for the worse. A drunken groom causes an accident that damages Beauty's knees. Due to fashion trends, a horse with blemished knees is deemed unfit to pull a carriage, leading Beauty on a journey through various middle and lower-class jobs. Although he spends three years with a wonderful cab driver, the work is grueling and exhausting. Eventually, he is subjected to even harsher labor, collapses, and is nearly sent to the slaughterhouse. Fortunately, he is sold to a farmer who restores his health and provides him with a pleasant home for the remainder of his life.

The individuals and horses Beauty encounters in his different jobs each have stories that shed light on the conditions of horses during that era and reveal the character of their caretakers. Beauty's gentleness and goodness, even in tough times, make him a lasting favorite among readers.

Blantyre

Blantyre is a guest at Earlshall Park and is riding Beauty when Lady Anne has an accident. He sends a workman and Beauty for help and later commends Beauty.

Ellen Blomefield

Ellen is one of Black Beauty's final owners. She and her sister employ Joe Green.

Miss Lavinia Blomefield

Along with her sister Ellen, Lavinia is one of Black Beauty's last owners and Joe Green's employer.

Mr. Blomefield

Mr. Blomefield is the vicar at Birkwick. He purchases Merrylegs and employs Joe Green after the Gordons leave England.

The Butcher

The butcher character exemplifies a business owner who must appease thoughtless customers, resulting in the suffering of his horse.

Captain

Captain is Beauty's companion as a cab horse with Jerry Barker. He served in the cavalry during the Crimean War and shares his experiences of combat with Beauty. Captain is injured in an accident caused by a drunk drayman and must eventually be put down.

Prince Charlie

Prince Charlie is a coster-boy whom Jerry nicknames because of the loving bond he shares with his cart pony, which suggests he will one day become an exceptional driver.

Duchess

Duchess is Black Beauty's mother. Named Duchess but often called "Pet" by Farmer Grey due to her friendly nature, she advises Black Beauty to be gentle and good, perform his work willingly, and never bite or kick.

Lord George

When Ginger refuses to wear the bearing rein at Earlshall Park, she is given to young Lord George for hunting. However, he ruins her with his hard riding.

Ginger

Ginger, a tall chestnut mare with a "long handsome neck," has an ill-tempered nature due to mistreatment. Beauty first encounters her at Birtwick Park, and they are later sold together to Earlshall Park. At Earlshall, Ginger resists the bearing rein and is subsequently used as a hunter. After being overworked, she is given a year in pasture to recover but never fully regains her health. She passes through several owners until she ends up as one of Skinner’s overworked cab horses. When Beauty finds her, Ginger is so exhausted and mistreated that she longs for death. Soon after, Beauty witnesses her lifeless body being carted away.

Miss Flora Gordon

Flora is one of Squire Gordon’s two daughters at Birtwick Hall.

Miss Jessie Gordon

Jessie is the other daughter of Squire Gordon at Birtwick Hall.

Mrs. Gordon

Mrs. Gordon is Squire Gordon’s wife and the one who named Black Beauty. Her illness prompted the Gordons to leave England and sell all their horses.

Squire Gordon

Squire Gordon owns Birtwick Park and is Black Beauty's first owner once he is old enough to be sold by Farmer Grey. The Squire is a kind man known for advocating humane treatment of horses.

Governor Grey Grant

Governor Grant, a fellow cab driver and friend of Jerry Barker, serves as a peacemaker and advisor for all the cab drivers. He assists when Jerry is ill and purchases Hotspur when the Barkers leave London.

Joe Green

Joe Green is the stable boy who replaces James Howard at Birtwick Hall. Initially, he nearly kills Black Beauty by improperly caring for him after a hard ride but later learns proper horse care. Joe reports a man for beating two horses, leading to the man's imprisonment. When the Gordons leave England, Joe and Merrylegs move to live with the Vicar. Still employed by two of the Blomefield sisters when Beauty is bought by them, Joe recognizes Beauty from Birtwick and is overjoyed to reunite with him.

Farmer Grey

Black Beauty spends his first four years in the meadow of Farmer Grey, who is known for breeding and training high-quality horses with great care.

Hotspur

Hotspur is the horse that replaces Captain in Jerry’s stable. Governor Grant buys him when Jerry relocates to the countryside.

James Howard

James Howard, the stable boy at Birtwick Hall, rescues Beauty and Ginger from a barn fire. His exceptional skills with horses lead to a recommendation from Squire Gordon and John Manly for him to become the head groom at another estate. Joe Green then replaces him.

Jakes

Jakes is the foreman for the baker to whom Jerry sells Beauty. He responds to a lady’s plea to remove the bearing rein from Beauty when he is pulling a heavy load.

Justice

At Birtwick Hall, Beauty often converses with Justice, a robust and good-natured roan cob used for riding or pulling the luggage cart.

John Manly

John Manly serves as the coachman for Birtwick Hall. He is a skilled caretaker and a strong advocate for proper horse care. He provides James Howard with sage advice before James advances his career and also trains Joe to become an excellent groom. John Manly is among the first characters Sewell uses to express moral viewpoints.

Merrylegs

The friendly Merrylegs is a plump gray pony who enjoys playing with the children at Birtwick Park but refuses to tolerate any misbehavior. This character may be inspired by Sewell’s own beloved gray pony. Merrylegs accompanies Joe Green to the Vicar’s when the Gordons relocate.

Old Ba-a-ar Hoo

Old Ba-a-ar Hoo is an elderly gentleman who delivers coal. Jerry asserts that he exemplifies how a horse can be content even in poor conditions if treated well.

Sir Oliver

Sir Oliver is an older brown horse at Birtwick Hall with a shortened tail, cut to satisfy a fashion trend. His story prompts a discussion about the practice of clipping tails and ears on dogs.

Peggy

Peggy is a beautiful, dappled brown mare who works alongside Beauty at the livery stable. She has an uneven gait due to her short legs and mishandling by poor drivers. However, Peggy is a gentle horse and is fortunate to be sold to some ladies for country driving, ensuring her a good life.

Rory

Beauty is paired with Rory at the livery stable until a carriage accident injures Rory, relegating him to pulling a coal cart.

Seedy Sam

Seedy Sam is a cab driver employed by the unscrupulous Nicholas Skinner. He explains to Jerry the harsh lives endured by men and horses working on shares for owners like Skinner and the compromises he feels compelled to make to survive. Sam eventually dies from overwork.

Nicholas Skinner

Nicholas Skinner owns a fleet of low-quality cabs and horses, which he rents out to drivers. He overworks Beauty to the point of collapse, nearly sending Beauty to slaughter.

Reuben Smith

Reuben Smith is entrusted with overseeing the stables at Earlshall Park in York’s absence. Though skilled with horses, he struggles with alcoholism. During one of his drunken episodes, he has a riding accident that results in his death and leaves Beauty with scarred knees, making him unsuitable as a carriage horse.

Farmer Thoroughgood

Farmer Thoroughgood is persuaded by his grandson to purchase Beauty at an auction and attempt to rehabilitate him. Thoroughgood eventually finds Beauty’s final home with the Blomefield sisters.

Willie Thoroughgood

Willie is Farmer Thoroughgood’s grandson. After convincing his grandfather to buy Beauty, Willie carefully tends to Beauty, helping him recover sufficiently to be sold to the Blomefield sisters. Willie’s diligent care allows Beauty to enjoy a good life in his later years.

Mr. York

Mr. York oversees the stables at Earlshall Park. He treats the horses well and is compassionate enough to employ Reuben Smith, even though Smith struggles with alcoholism. However, York fails to oppose the mistress when she insists on using the bearing rein on the horses.