He was orphaned at age five when his parents drowned in Boston Harbor, and then raised by his aunt Dottie, a cold, stingy woman who mocked him as a "sissy.” As a teenager, he attempted unsuccessfully to run away from his aunt's home to New York City before finally moving there at age 20 to pursue an unsuccessful career as an actor.

Ripley subsequently made a meager living as a con artist utilizing his skills in "forging signatures, telling lies, and impersonating practically anybody.”[4] Ripley is paid to go to Italy by shipbuilding magnate Herbert Greenleaf to convince his son Dickie, a half-remembered acquaintance, to return to New York and take over the family business.

Ripley befriends the younger Greenleaf and falls in love with the rich young man's indulgent, carefree lifestyle; he also becomes obsessed with Dickie himself.

He occasionally assists small-time gangster Reeves Minot with lucrative forgery and smuggling jobs, but he avoids direct involvement in crime as much as possible to preserve his shady reputation.

Ripley is also a silent partner in a gallery that markets counterfeit works by the artist Derwatt, who has actually been dead for years.

When they discover that he murdered Murchison and threaten to expose him, Ripley pursues them with the aid of Ed Bradbury, one of his business partners in the Derwatt forgery scam.

Highsmith characterizes Ripley as a "suave, agreeable and utterly amoral" con artist and serial killer who always evades justice.

He is polite, friendly, and cultured, and dislikes people who lack such qualities; when the Pritchards appear in Ripley Under Water, their poor taste and manners immediately offend him.

[7] In Ripley Under Ground, he recalls "turning green" during his wedding, then going impotent with laughter while having sex with Heloise during their honeymoon.

It's insidious, the way Highsmith seduces us into identifying with him and sharing his selfishness; Ripley believes that getting his own way is worth whatever price anyone else might have to pay.

[14] In 2015, The Hollywood Reporter announced that a group of production companies were planning a television series based on the novels.

[16] In 2019, the show was ordered to series at Showtime, with actor Andrew Scott playing the lead role and writer-director Steven Zaillian replacing Cross.

[18] Of the Ripley portrayals that Highsmith saw, she praised Delon's performance in Purple Noon as "excellent"[9] and described Jonathan Kent as "perfect".

[13] She initially disliked Hopper's Ripley in The American Friend, but changed her mind after seeing the film a second time, feeling that he had captured the essence of the character.

[19][20] In Joanna Murray Smith's 2014 play, Switzerland, Tom Ripley comes to life and visits Highsmith, planning to kill her.