In most appearances (except during the World War II era), Popeye is a middle-aged sailor with a unique way of speaking, disproportionately muscular forearms with two anchor tattoos, thinning hair, and an ever-present corncob pipe (which he toots like a steamship's whistle at times). Popeye is generally depicted as having only one eye, his left. In at least one Fleischer cartoon, Bluto refers to Popeye as a "one-eyedrunt." Mostly quiet as to how he lost his right eye, the sailor claims it was in "the mos' arful battle" of his life with Sea Hag's vulture. Later versions of the character had both eyes, with one of them merely being squinty, or "squinky" as he put it. According to the official site, Popeye is 34 years old and was born in a typhoon off Santa Monica, California. This appears to be a retcon, as in the 1938 cartoon "Goonland", Popeye sets out to find his long-lost father, who had left when Popeye was born. Popeye himself states that his father had been gone 40 years. Much later, in Popeye, the Ace of Space, his original age is given as 40 by an alien aging machine. In 1934, Segar stated that Popeye was born in Victoria, Texas.^[2]

Popeye's strange, comic and often supernatural adventures take him all over the world and place him in conflict with enemies such as the Sea Hag and Bluto. His main base of operations is the fictional town of Sweethaven. Popeye's father is the wayward sailor Poopdeck Pappy, who is somewhat irresponsible and is represented as having a fleeting association with Popeye in some sources.^[which?] Popeye's sole sweetheart over the years is Olive Oyl; although the two characters often bickered in early stories. Popeye is the foster father of Swee'Pea, an infant foundling left on his doorstep. (Sweet Pea is a term of affectionused by Popeye; in the cartoon We Aim to Please, he addressed Olive Oyl as "Sweet Pea" at one point.)

In addition to a gravelly voice and a casual attitude towards grammar, Popeye is known for having an apparent speech impediment (a common character-distinguishing device in early cartoons), which either comes naturally or is caused by the ever-present pipe in his mouth. Among other things, he has problems enunciating a trailing "t"; thus, "fist" becomes "fisk" (as sung in his theme song, which makes it conveniently rhyme with "risk") and "infant" becomes "infink." This speech impediment even found its way into some of the titles of the cartoons.

Popeye is depicted as having superhuman strength, though the nature of his strength changes depending on which medium he is represented in. Originally, the comic-strip Popeye gained his strength and invulnerability in 1929 by rubbing the head of the rare Whiffle Hen.^[3] From early 1932 onward, especially the cartoons, Popeye was depicted as eating spinach to become stronger. The animated shorts depicted Popeye as ridiculously strong but liable to be pummeled by the much larger Bluto before his eating of the spinach.

When fed up with this treatment or exhausted, he would eat spinach, which would instantly restore and amplify his strength to an even greater level. In the comic strips, spinach is presented as a panacea, infusing Popeye not only with his extraordinary strength, but also making him invulnerable to all sorts of threats (including bullets, a basilisk's petrifying gaze, or aliens' weapons) and even capable of feats like flight or extraordinarily fast swimming (usually with the aid of his pipe as a propeller or hydrojet). In the animated shorts, Popeye's ingestion of spinach—which is almost invariably canned—is equally fanciful and often involves squeezing the can until the top opens, or sucking the spinach through his pipe, and on rare occasions, even ingesting the can as well. Occasionally, spinach has a similar invigorating power on other characters.

Other differences in Popeye's story and characterization show up depending upon which medium he is presented in. While Swee'Pea is definitively the ward of Popeye in the comic strips, he is often depicted as belonging to Olive Oyl in cartoons. The cartoons also occasionally feature family members of Popeye that have never appeared in the strip, notably his look-alike nephews Peepeye, Pupeye, Pipeye and Poopeye. Popeye also had a red bulbous-nosed dog named Jeep-Jeep, who ate geraniums and vanished without notice.^{[clarification needed]}

Even though there is no absolute sense of continuity in the stories, certain plot and presentation elements remain mostly constant, including purposeful contradictions in Popeye's capabilities. Though at times he seems bereft of manners or uneducated, Popeye is often depicted as capable of coming up with solutions to problems that (to the police, or, most importantly, the scientific community) seem insurmountable. Popeye has, alternatively, displayed Sherlock Holmes-like investigative prowess, determining for instance that his beloved Olive was abducted by estimating the depth of the villains' footprints in the sand, scientific ingenuity (as his construction, within a few hours, of a "spinach-drive" spaceship), or oversimplified (yet successful) diplomatic argumentation, by presenting to diplomatic conferences his own existence (and superhuman strength) as the only true guarantee of world peace.

Popeye's vastly versatile exploits are deemed even more amusing by a few standard plot elements. One is the love triangle between Popeye, Olive and Bluto, and the latter's endless machinations to claim Olive at Popeye's expense. Another is his (near-saintly) perseverance to overcome any obstacle to please Olive – who, quite often, renounces Popeye for Bluto's dime-store advances. She is the only character Popeye will permit to give him a thumping. Finally, in terms of the endless array of villain plots, Popeye mostly comes to the truth by "accidentally" sneaking on the villains, the moment they are bragging about their schemes' ingenuity, thus revealing everything to an enraged Popeye, who uses his "fisks" in the name of justice.