Larry is a bodybuilder and is often seen competing or working out with other sea creatures. He is always seen in his swim trunks, even when he is not at the beach. He regularly goes to Bikini Bottom's beach, Goo Lagoon and works as a lifeguard there, as seen most notably in "SpongeGuard on Duty." Larry is one of the strongest creatures in Bikini Bottom. Larry is very popular and is idolized by many other beachgoers. In "Band Geeks," it is stated that Larry's heart once gave out from too many tanning pills, and in "Roller Cowards", he is revealed to have a bad armpit odor that is caused by adrenaline. In the event Patrick For President, Larry lost a campaign for Bikini Bottom president to Patrick, who was elected in a landslide victory with 100% of the votes.
Larry's implied parents appear in "SpongeGuard on Duty." However, they are not lobsters; they are generic "old person" character models. Larry kicks his own parents off of the beach for being too "old and unsightly," in an ironically polite manner.
He is a popular individual who has many adoring fans who crowd around him on the beach. He takes pride in being a lifeguard, knowing that he is the only thing separating the Bottomites from a watery grave. He has been seen to be furious at other characters in "Bubble Buddy" and "A Life in a Day." He has even kicked out his own parents for being old, but so politely they did not take offense to it. Despite his muscular physique, he is somewhat cowardly as shown in "A Life in a Day."
While Larry is strong and polite, he is sometimes full of himself. This is seen when he completely ignores the Flying Dutchman, instead ranting about his body. There is also a part of the song "Ripped Pants" where the lyrics are "when big Larry came 'round just to put him down." Earlier in the episode, he also acknowledges SpongeBob as something of an underling, similar to Squidward.
When Larry was young, he was assumed to have been adopted by Mable and Dennis.
Larry's first actual interaction with SpongeBob is in "SpongeGuard on Duty," and he is impressed when he sees a drop of ice cream on SpongeBob's nose, thinking it is sun tan lotion.
In "Pet or Pests," when SpongeBob approaches Larry to ask about his worm pets, Larry asks, "Do I... know you?" SpongeBob replies, "Probably not." This shows that, although they have interacted before, they do not remember each other. SpongeBob's reply shows that he expects Larry not to know him at all.
In the episode "Larry's Gym," Larry attempts to build SpongeBob in his own image, and succeeds. After Larry loses his shape, SpongeBob acts as Larry's personal trainer, and by the end Larry gets back in shape.
In "SpongeGuard on Duty," Patrick dislikes all lifeguards, including Larry. However, at the end, Larry is seen helping Patrick learn to swim after he saves him from nearly drowning in shallow water.
In "A Life in a Day," Larry the Lobster seems not to know Patrick. He looks for examples of weaklings around him, sees SpongeBob and Patrick, then tells his adoring crowd: "Just look at 'em. Spineless, weak, afraid of their own shadows. Pathetic." Patrick tries to turn his life around and live like Larry does, but he eventually loses enthusiasm for this after taking a stunt too far. SpongeBob pressures Patrick into doing one last dangerous stunt, during which Larry tries (and fails) to save them.
In "You Don't Know Sponge," after upsetting SpongeBob by failing to recall anything about him, SpongeBob sees Patrick walking with Larry while shopping. This initially confuses SpongeBob, as he believes Patrick has already moved on from their friendship and tried to find a new friend.
Larry gets along well with Sandy, since they are both into sports and are very athletic. In "Ripped Pants," he invites Sandy and SpongeBob for weight lifting, and they both impress each other with their skills. Also, in "MuscleBob BuffPants," he and Sandy both participate in the Anchor Toss.
In "Squirrel Jelly," Sandy brutally beats Larry by hitting him hard with a volleyball and leaves him injured. He yells at her for it after she realizes that she has taken her competitiveness too far.
Larry and Squidward had not been seen together until the ninth-season episode "Squid Plus One." Squidward searches for a new friend, but their chance at friendship ends after Squidward mocks him about protein shakes. Larry promptly beats Squidward to a pulp.
Larry also appears playing volleyball on a team with Squidward and Mr. Krabs against Sandy in "Squirrel Jelly."
Like Squidward, Mr. Krabs did not interact with Larry until the ninth season, but they seem to get along with each other pretty well. In "Larry's Gym," when Mr. Krabs hears that his first gym visit is free, he vows to stay there forever. Mr. Krabs teases Larry for losing his shape.
In "The Check-Up," Larry agrees to pose as Mr. Krabs in order to help the latter pass his physical. In "Larry the Floor Manager," Mr. Krabs takes a vacation and makes Larry the Lobster the temporary manager of the Krusty Krab.
In "Squirrel Jelly," Larry plays volleyball on a team with Mr. Krabs and Squidward against Sandy.
"Anybody up for some volleyball?"
"SpongeGuard on Duty"
"Please do not land flying ice cream trucks on the bathers."
"You know, SpongeBob, the babes in the big chair are great, but the best part is knowing that you're the only one standing between these good people and a watery grave. That's what it's all about. Their lives are in your hands now, 'cause I have a date with the tanning booth. So long."