Like Master Roshi, he enjoys smoking cigars and is a pervert, but considerably less so. His favorite hobby is collecting women's underwear. Oolong is cynical and cowardly, and he is not hesitant to admit it; in fact, he is downright proud of his wimpish traits. Ironically Oolong is three years younger than Goku, Bulma points this out with the line "what kind of kid acts like a middle aged pervert" in the original Japanese version of episode 6. A running gag in both Dragon Ball and Dragon Ball Z is Oolong constantly being beaten up by Bulma during the World Martial Arts Tournaments due to her anxiety over the fighting. At one point, Bulma became so habitually accustomed to this that when Oolong moved away from Bulma before she could hit him, she found it surprising and looked for him. He is also there to provide comic relief and is often very sarcastic. Similar to the stereotypical depiction of pigs, he is also shown at times to be a huge glutton, as in Broly - The Legendary Super Saiyan, he was enjoying the immense feast that Paragus prepared for him, Goku, and Roshi, and even went as far as to threaten to eat the entire banquet if Goku didn't start eating (as Goku at the time was pondering who the Legendary Super Saiyan was after deducing it wasn't Paragus).

He is also perceptive enough to realize the anonymous female fighter at the 23rd World Tournament was in fact the grown-up Chi-Chi, a revelation that shocked the rest of his friends none of whom recognized her.