The two do not interact for a majority of the first season, due to them being on separate teams, and befriending different people. Duncan and Leshawna's conflict arises mainly because of their clashing personalities during the merge, but the two end up solving their conflict in Trial by Tri-Armed Triathlon.
Their truce does not last long, as they are put on the same team in Total Drama Action. Leshawna has a personal dislike of Duncan because he constantly bullies Harold, for whom she has a soft spot for. Duncan becomes more enraged with her, as it is discovered that Leshawna faked her crying in order to get a reward for herself. However, this doesn't stop Leshawna from trying to make an alliance with Duncan and Harold later on in the competition. However, this effort also fails, as he started the plot to her elimination.
In order to protect themselves from the newly formed guys' alliance, Leshawna supports voting out Duncan, calling him a "criminal" and stating that she does not trust him. This plan fails, as he is spared from elimination.
In the confessional, Duncan states that Leshawna has been warming up to him lately and calls him a "nice guy", much to his annoyance. The two of them are paired up for the challenge and immediately get into an argument to decide who gets be the eater for the first challenge. They have an arm wrestling competition to settle this, in which Duncan wins by cheating. When the challenge begins, Leshawna feeds Duncan in a fast pace, either out of being angry at him for cheating or trying to keep up with the other teams and constantly ignores his pleas to slow down. After the first challenge, when Chris taunts the contestants about the wimp key, Leshawna and Duncan give each other threatening looks with Duncan daring Leshawna to take the key.
As they are heading to their canoe, the two continue arguing over on who should sit in the front. Duncan nearly states Leshawna is overweight, leading Leshawna to threaten him not to finish his sentence. En route to Boney Island, Duncan complains about being the only one paddling, and after some bickering, Leshawna mentions that Duncan has a nice side and proclaims he is actually a nice person despite his "tough guy" talk. Duncan feigns ignorance, until she brings up the incident about DJ's bunny that Courtney told her about. Duncan comes clean and tells her that he knew from experience how DJ felt after losing a pet, because his dog Petey had run away from home when he was six years old, and he didn't want DJ to suffer like he did. After Duncan agrees to paddle, Leshawna tells him that his secret is safe with her Once they reach Boney Island when one has to piggyback the other, Leshawna tackles Duncan to the ground when he mentions he is not lifting her due to her weight. She is later seen piggybacking Duncan as they reach the cave, however, woolly beavers, appear to be there. Duncan mocks Leshawna that she can beat them, and she runs away saying that nobody is that tough. At the final challenge, Leshawna comes to Duncan's aid when Chris is mocking Duncan's affection for Courtney by throwing a wooden head at the host. She says that no one has to be tough all the time, to which the two smile at each other. Afterwards, they win the final challenge.
After watching Duncan's performance, Leshawna, along with Chef, Chris and Heather are moved to tears.
Leshawna grows more hostile with Duncan, as she notices that he is picking on Harold a lot. She claims that she has her eye on Duncan, which also shows signs of her getting defensive of Harold.
While the two of them are walking back to the trailers, Leshawna proposes to Duncan that the two of them and Harold, should form an alliance against Heather, but he laughs at the idea of partnering with Harold, annoying Leshawna. During the first hospital challenge, Leshawna defends Harold again after Duncan pulls his pants down.
After the castmates suddenly suffer many symptoms from a mysterious disease, Leshawna and Duncan work together to help all the others, as they were the only contestants are not infected. Later, when Harold is afflicted with a phony disease, Leshawna knocks away Duncan when he attempted to stick a rectal thermometer in Harold's mouth. In the end, Duncan and Leshawna find out that everyone is actually healthy, winning the challenge. While deciding which member of their team should earn the reward, Duncan nominates Leshawna after he sees her crying out of concern for her friends' safety.
When Duncan is making fake blood in this episode, Leshawna gives him respect, saying that it looks very realistic. She is quick to withdraw her respect when Duncan revealed he and his brothers have used the fake blood to scare kindergartners, and that he had once given twelve five-year-olds seizures.
When Leshawna accidentally admits she faked her crying two episodes earlier, Duncan, along with Heather, was very angry with her, and perhaps the angriest of all the other Gaffers. Upon finding out about her deception, he pointed a finger at her and angrily declared, "You're a total sham!"
Duncan continues to bring up what Leshawna had done three episodes ago in anger. He even comments that as far as he knows, she is basically "off the team." Despite this, Leshawna along with Heather, allow Duncan to take charge at the first round of the challenge in favor of Harold. As her farting gets out of control, Duncan abandons the team, growing annoyed with all of them.
Duncan refuses to let Leshawna forget about her lie to the team, even turning Harold against her. Leshawna swears revenge on all of them, right before she gets locked in a vault for the bank heist challenge. Duncan convinces the team to abandon Leshawna in an attempt to catch up with the Killer Grips, saying he doesn't need the bank robbery equipment locked in the vault with Leshawna, leaving her in the vault for the entire day, further deepening the enmity she feels towards Duncan.
Duncan is angry with Leshawna when she laughs at Heather's loss during the challenge, asking her which team she is on, to which she responds she's on theirs but that doesn't mean she can't have a satisfaction of Heather's failure.
Like everyone else, Duncan is angered when he watches Leshawna making some rude comments about the other contestants during her spa ride with her cousin, Leshaniqua, from a video on Courtney's PDA. She makes fun of Duncan for acting like a bad boy, but when Courtney is around, she drags him around by his eyebrow ring. Despite the animosity towards Leshawna after seeing the video on Courtney's PDA, Duncan decides to join her and Harold in voting off Heather as he liked Leshawna's apology cheer.
After Leshawna is complaining about the food, Duncan is glaring at her, along with everyone else, due to Leshawna making rude comments about the other contestants in the previous episode. Duncan then admits that he trusts no one, but himself. Leshawna also attempts to form the alliance between herself, Duncan, and Harold again but succeeds this time.
Duncan and Harold dump Leshawna and their new alliance in order to join Justin to form the new guys' alliance. Leshawna also betrays the alliance by teaming up with Lindsay and Beth to vote Duncan off, as it will mess with Courtney's head. At the elimination ceremony, Leshawna is successfully voted off over Duncan. As she's leaving, Leshawna tells Harold to stand up for himself and "kick Duncan's butt."
In Leshawna's Lame-o-sine clip, she is admittedly surprised she was voted off and didn't expect that her "mani-pedi" would cost her the million dollars. She does not blame Harold for voting her off, and immediately believes that Harold was bullied into it by none other than Duncan. Leshawna's anger begins to reach its boiling point as she steams that that was just one more reason why she couldn't stand Duncan. Leshawna suddenly explodes, ripping a cushion off the Lame-o-sine and smashing it into the window in a rage. The tape is cut off but returns to find Leshawna has cooled off, but not without destroying the interior of the limo. She then threatens Duncan over the tape, warning him that she is coming for him and that if there is a single scratch on Harold, "Leshawna will be gettin' all up in your business!"
When Harold is talking about how delicate Leshawna is, Duncan says that she is about as delicate as a freight train, prompting Harold to punch Duncan.
Leshawna is in awe when she sees a video of Duncan showing his sweet side.
- There is a connection between this conflict and the conflict between Duncan and Harold, as Harold has feelings for Leshawna.
- They have both placed fifth and then eighth in two seasons in a row.
|Interactions with||Everyone | Alejandro | Beth | Chef Hatchet | Chris | Courtney | DJ | Geoff | Gwen | Harold | Heather | Leshawna | Mike | Owen | Trent | Zoey|
|Other content||Guys' alliances | Scruffy|
|Interactions with||Everyone | Bridgette | Duncan | Gwen | Harold | Heather | Lindsay|