"I'm such a bitch."
She has never actually been shown on the show, and therefore served as a running gag (as the unseen character is a popular literature device). On The Click on the-n.com (which is now redirected to teennick.com), there is a Degrassi Mini titled "Be Aware of Heather Sinclair" in which Heather is still never seen, but we are shown the other characters' reactions to her mean comments instead. It is implied that she graduated in 2006 according to the occurring events in her Degrassi Mini.
Heather is first mentioned by Terri MacGregor in the season one episode Parents' Day. She mentions to Ashley Kerwin that even Heather says Ashley's morning announcements are better than the N.A.K. hosts. Terri says that she has an agent, to which Paige Michalchuk is disgusted because of her apparent overbite.
In Cabaret, Paige tells Terri that her duo with Ashley sounds lamer than Heather's Highland Sword dance.
In When Doves Cry (1), Craig Manning is giving a speech in Mrs. Kwan's class. When he finishes, Mrs. Kwan calls on Heather. Heather is seen walking behind Craig, only showing part of her legs, which were covered by her pants.
In Mercy Street, Paige calls Heather's eyebrows "tragically over-plucked", and Emma says her tweezers should be confiscated.She would be mentioned in passing throughout the next seasons, and she would almost be shown in the season four episode Neutron Dance during a yoga class, but her arms cover her face.
In Islands in the Stream, she is partners with Emma for the tryouts for Degrassi's official Trivia Team. She is ranked at #2 on Rick Murray's list of hot twenty girls in the entire school.
It is mentioned in Time Stands Still (1) that she had contracted mono before the Whack Your Brain Contest, allowing Jimmy to take her spot. This would eventually lead to him being shot and paralyzed by Rick Murray.
She is mentioned in West End Girls when Ashley says to Craig they need to get to the food before Heather Sinclair does.
In Foolin', Toby Isaacs tells J.T. Yorke that Heather auditioned for the video announcements with a booger dangling from her nose hair. When J.T. fails his audition for the video announcements because he is too preoccupied over the fact that Liberty is pregnant, Liberty says that Heather Sinclair gets the job.
In The Lexicon of Love (2), Paige tells Marco that she has had feelings for another girl, and Marco guesses that the girl is Heather Sinclair, as he has seen the way she looks at Paige. She responds to the thought with an "ew".
In Our Lips Are Sealed (2), Paige and Alex laugh over the fact that she is wearing volley shorts to school.
In Can't Hardly Wait, Ashley puts her hands over Jimmy's face and tells him to guess who. He guesses Heather Sinclair, and she tells him that he is funny.
In the Degrassi Mini, Be Aware of Heather Sinclair, she terrorizes the students of Degrassi and states that Peter Stone is hot and evil. At the end of the clip, Mr. Simpson calls her down to the Main Office because she parked her car in the handicap parking space again. She is still unseen for most of this short (as the camera is from her point of view), though we get an incredibly short glimpse of her face when she closes her locker door.
In the Degrassi Mini, Toby Dynamite, Heather is running for student council president against Liberty Van Zandt. She says "If you vote for me, I'll make sure there are no more pesties in the food! I'll make sure all the school dances include a free-" she is still talking, but is cut off by Snake talking to Toby and Liberty. The last thing she says is "Vote for Heather!" Then, for her "skit", she plays the trumpet.
In season seven, Holly J., Heather's younger sister, transferred to Degrassi Community School with the other Lakehurst students. Holly J. proved that she followed in her footsteps; she was pretty, popular, and mean.
On another Degrassi Mini, "Queen Bees", Holly J. and Paige Michalchuk then have a face off for who is a better queen bee. When told that Holly J. is Heather's younger sister, Paige responds "She's the devil's spawn!"
When her family was having financial problems in Money for Nothing, Heather sent Holly J. a check so that she could go to the Cheer Leading Regionals. She told her mother that no sister of hers would miss the Regionals.
Seasons 10-11U Don’t Know (1), Holly J. admits that Fiona is more a sister to her than Heather ever was. While Holly J. is looking for pictures of herself as a child, she comes across old pictures of Heather, Heather's pet turtle, and their family, but none of herself. It is revealed that Heather had a nose job to fix the "Sinclair schnauze" she inherited. Heather does not have a compatible blood type with Holly J., so she is unable to donate a kidney to her. Their mother later tells Holly J. that Heather was a complicated birth, which made it so she was no longer able to carry children.
In #ThrowbackThursday, She is mentioned by Paige.
- Heather is the older adopted sister of Holly J. Sinclair.
- In The Lexicon of Love (2), Marco Del Rossi tells Paige Michalchuk that Heather 'looks' at her, hinting that she could have been a lesbian or bisexual.
- Heather went to Degrassi Community School for her entire education, while her sister Holly J. was placed in Lakehurst Secondary School and would only transfer to Degrassi after it burned down. This is considered unusual by some since they lived in the same home, though it is not uncommon for siblings to attend different schools.
- It was rumored that she would go to Holly J.'s graduation and might have been shown. This rumor was proven false.
- Heather is almost revealed in Neutron Dance, but her arms are covering her face.
- Heather has an AB blood type, and is 6 years older than Holly J. (3 years without the retcon).
- She had a pet turtle.
- She has had a nose job, thanks to the infamous "Sinclair Schnauze" mentioned by Holly J.
- Heather's birth was so complicated that her mother was never able to have any more children.
- After Heather Farrell, Heather Sinclair is the second "Heather" in the Degrassi Franchise and the first "Heather" not to be shown on camera. The second is Heather Poulette.
- Heather Sinclair is the second unseen character in the Degrassi Franchise. The first was Mr. Lawrence and the third was Heather Poulette.
- Heather has an overbite, stated by Paige in Parents' Day.
- She comes off mean and rude just like her younger sister Holly J.
- She is always being talked and gossiped about by the students at Degrassi.
- She had an unseen rivalry with Paige.
- She is said to be a bitch by everyone.
- In the Degrassi Mini Be Aware of Heather Sinclair, she seemed to look a lot like Paige in a quick mirror reflection, though this was in Paige's dream.
- Her voice is said to be a mixture of Paige and Emma's.
- She is really bad at the trumpet.
- Heather sent Jimmy a get well card after he was shot.
- Heather performed a dance in Degrassi's Christmas show in Holiday (2).
- In the 2015 interview Straight Talk with Adamo Ruggiero, Charlotte Arnold said that she would like to see Amy Schumer play Heather.