Dr. Frederick Treves is a 31-year-old ambitious surgeon who views medical science as a civilizing force. Entrenched in strict Victorian social rules, he maintains an idealized view of morality and propriety. He initially approaches John Merrick purely as a fascinating anatomical specimen, paying to examine him for an academic lecture. As he rescues Merrick from public abuse, Treves adopts the role of a savior, determined to teach Merrick how to exist as a typical man in polite society.

John Merrick is a young English man living with an extreme, highly visible physical condition that has caused him to be outcast and exhibited in "freak shows." Despite an early life of severe abuse and institutionalization in the workhouse, he possesses an agile mind, artistic sensitivity, and an innate spiritual curiosity. Denied basic human connection for most of his life, he quickly absorbs literature, religious teachings, and societal rules once given safe harbor at the London Hospital.

Ross is a transactional and crude entertainment manager who relies on exploiting human differences to survive. He views Merrick entirely as a commodity, using physical force, intimidation, and verbal abuse to keep him compliant. He rationalizes his behavior by claiming he rescued Merrick from the workhouse, using this narrative to justify his ongoing theft and mistreatment.

Carr Gomm is the pragmatic, realistic administrator of the London Hospital. He understands that the hospital relies heavily on public perception and elite funding, and he recognizes the financial and reputational boon that Merrick's high-profile case brings to the institution. Unlike Treves, Gomm lacks illusions about moral purity, preferring practical solutions to complex problems.

Mrs. Kendal is a renowned, successful stage actress operating in London's elite circles. Treves enlists her to meet Merrick, assuming her professional acting skills will allow her to hide the revulsion that has driven other women away. Instead, she finds herself genuinely charmed by Merrick's intellect, leading to an honest friendship that challenges Victorian standards of propriety.

Bishop Walsham How is a prominent Anglican clergyman who views religion as the ultimate cure for human suffering. He strongly supports British imperialism, believing it spreads Christian enlightenment. He takes on Merrick as a spiritual pupil, instructing him to repress his physical desires and mold himself into an idealized, completely chaste Christian figure.

Lord John is an aristocratic member of London's upper crust who visits Merrick once the hospital resident becomes a celebrated cause among the elite. He uses his visits to perform charity publicly while privately leveraging his connections to Treves and the hospital for questionable financial investments.

The Pinheads are three young women with microcephaly who perform in a Belgian fair under the exploitative title "Queens of the Congo." They suffer physical threats and verbal abuse from their manager if they fail to perform their patriotic act.

Nurse Sandwich is a medical caretaker who previously worked in severe conditions in the Niger and Ceylon. She boasts to Treves about her iron constitution and lack of superstition, claiming she is perfectly suited to care for Merrick.

Snork is a working-class employee at the London Hospital. Despite strict rules against treating Merrick as an exhibit, his intense curiosity leads him to intrude on Merrick's privacy.

Porter is a hospital worker desperate to maintain his employment to support an ailing wife and multiple dependent family members. His decision to break the rules and look at Merrick puts his family's survival at risk.

The Man is a cruel entertainment manager in Belgium. He exploits the women under his control by forcing them to sing praises to the Belgian king, threatening to send them to an asylum if they fail.

Princess Alexandra, the Princess of Wales, is a member of the British royal family who joins the trend of high-society figures visiting Merrick. Her visit signals his total transition into a fashionable society cause.