* Thomas "Tom" Ripley: The protagonist, a charming and manipulative con artist who is hired to find and bring back a young American millionaire, Dickie Greenleaf.
* Dickie Greenleaf: The wealthy and carefree playboy Tom is sent to find. He is impulsive, selfish, and has a destructive influence on Tom.
* Meredith Logan: Dickie's girlfriend, a beautiful and intelligent woman who is initially attracted to Tom but later becomes suspicious of his intentions.
* Peter Smith-Kingsley: A friend of Dickie's who becomes entangled in Tom's schemes. He is a wealthy and arrogant man with a penchant for danger.
* Freddie Miles: A close friend of Dickie's who becomes a key player in Tom's efforts to impersonate him. He is loyal and gullible, making him an easy target for manipulation.
* Herbert Greenleaf: Dickie's father, a wealthy and influential businessman who is initially suspicious of Tom.
* Mrs. Greenleaf: Dickie's mother, a kind and compassionate woman who is initially sympathetic to Tom.
* The Police: The authorities investigating Dickie's disappearance, who become increasingly suspicious of Tom's involvement.
These characters are all intricately linked in a web of deceit, betrayal, and violence. The novel explores the themes of identity, morality, and the destructive power of obsession.