Tony Randall, Albert Finney, and Peter Ustinov had assayed the character, but Suchet made him his own, giving Poirot such specificity, both physically and in his remarkable deployment of props - including that portable ashtray he uses while promenading in his little duck walk around the English gentry's perfectly coiffed gardens.
Suchet insists he didn't manufacture any of Poirot's gestures and peculiarities, but simply followed Christie's instructions.
"I went back and read all the short stories. I started seeing a person I had never, ever seen before portrayed in the TV and film versions," the actor said in a recent phone chat. "So I made this big dossier of all his characteristics and mannerisms."
Poirot, who isn't shy about calling himself "the world's grrreatest detective," isn't your average Joe. "He's an eccentric," Suchet said. "He could be called by today's psychoanalysts an obsessive compulsive. . . . He loves order and method."
Suchet admits he's less than thrilled by some of Poirot's neuroses. "There are so many times when he would make me irritated," he said, "because he was just so fussy and irrational."
Like so many great crime-fighters, Poirot doesn't have time for hearth and home. "He's a loner," Suchet said. "He has chosen the life of the bachelor, while at the same time in his deepest heart he wished he had been married."
There's a melancholy about Poirot that persists. Perhaps it's caused by his acute awareness of the life he has given up. His lapel pin, which he wears just above his heart, serves as a constant reminder. A silver amphora topped by an elegant bunch of flowers and herbs, it was given him by a woman he once loved.
To Suchet, Poirot justifies sacrificing a normal life because he believes his work is a vocation, a sacred moral imperative.
"He believes his talent for being an exceptional detective was given to him by God," Suchet said. "He firmly believes his reason for being put on Earth is to help rid the world of crime. It's his calling."
Masterpiece Mystery!: Poirot
9 p.m. Sunday on WHYY-TV12 and Monday at www.Acorn.TV.