Sue is usually forgotten by Mike. When watching a drive-in movie, Axl claimed every parent has a favorite child; their mother, Frankie, denied it, but Mike implied it was true. Mike claimed he and Axl have a lot in common, such as football and other sports. Sue was upset. Sue took out a scrapbook and labeled it The Summer of Sue and Dad, and alerted her father about the project. Mike then started giving Axl negative attention and Sue none at all. Going to a fair, Axl had his school paper in his truck when he wrecked it and got towed. Frankie got upset and no one would listen to poor Sue. At the fair, Sue went to the lost and found for children wanting her family to wish to find her. After a while, the family came there to ask if they'd found the paper and left without Sue. At night, watching the fireworks, Axl stated he liked Mike better then Frankie. Sue got all worked up about how mom does everything for them. Younger brother, Brick Heck, later stated he liked dad better. Sue slipped out accidently she liked dad better. They all agreed to forget about it and have no favorites. Back at the house, Sue completed the scrapbook with fun pictures and Sue called it The Summer of Sue and Dad. For the longest time, Mike didn't know the potato place Sue worked at in the mall or what her JPLA meant. Mike kept trying to ask people to go with him to the basketball game and later took her out to lunch asking her what JPLA meant (it means Junior Peer Leadership Advisor) and agreed to attend one of her meetings. When everybody declined, Sue agreed to go but Mike ignored her. It then showed flashbacks of Sue asking to go places and she didn't get to. Frankie got angry that Mike wouldn't take Sue because she's a girl. Mike ended up taking Sue even when somebody else also agreed. Mike does go to a lot of Sue's sports tryouts even though she's terrible.
In The Bee, Mike was proud that Brick was in a spelling bee and won in his school. Mike continued to coach him. Both Mike and Frankie have forgotten Sue's birthday and took her to Chicago the weekend which Brick's championship was taking place. Frankie promised Sue could pick the hotel, restaurants, etc. on her "birthday trip."
In Season 5, they meet again while Darrin is fixing the air conditioning when Sue is taking out the trash. Darrin meets Sue over a garbage can where they meet and are still friendly. Darrin had moved on to a hairdresser with an Italian New York City accent and hairdo named Angel. Sue met Darrin and Angel in the front yard and Darrin told her that they were going to see a movie. Sue thought she was invited. Sue decided to spend a day with Angel and get her hair done. Sue asked Angel what she liked about Darrin. Angel liked his arms and face and obviously only liked him for his looks. Sue discussed this with Brad. And Brad said he supported Sue's decision but was really against breaking up with him.
When he said just the two of us she thought he meant without Angel. She came to her senses and realized that it was over. Darren saved Sue in The 100th, when Sue was about to be hit by the cow float that was on fire. In Sleepless in Orson, Darrin saw Sue kissing a troubled teenage neighbor, Derrick Glossner, and it seemed that he wanted to get her back, because he was holding a teddy bear and flowers.
In The Walk, several guys asked Sue to go to prom with her including Edwin (her boss), Brad Bottig, Darrin McGrew, Derrick Glossner, and Sean Donahue. Sue didn't go with Brad because she only really wants to go with Darrin. Sue called it off with the others. Once Darrin heard that Sean had been rejected because Sue had to many prom dates, Darrin left a message on Sue's phone telling her that he's not taking her to prom. Sue was very upset. Sue went to prom alone meeting up with "Weird Ashley" who Axl accidentally went to prom with twice. Darrin showed up at the prom and kissed Sue. After this, he performed a song about this called 'Magical Trash Can Kiss' in front of Sue and the other Ax-Men (Axl Heck and Sean Donahue).
- Sue has a Twitter account (@SueHeckWins), an Instagram account (@sueheckwins) and a Facebook page.
- Her full name is Sue Sue Heck due to an error made by her parents on her birth certificate. She almost changed her middle name to Lily once, but she changed her mind at the last minute after someone commented that "Sue Sue" was an interesting, unique name.
- Sue is left-handed, yet another rare characteristic.
- Sue had an overbite crossbite, which was overcorrected to an "unprecedented" overbite underbite.
- She loves peach scent.
- Sue believes in God.
- She often fights with her brother Axl.
- She created her own alter-ego - Suki, who, contrary to Sue, is right-handed and parts her hair on one side.
- She called herself a Frosh when she started High School.
- She almost once tattled on Axl for sneaking in after curfew, but he fessed up and she didn't, she got rewarded by Mike and punished by Frankie for this.
- She got hit on by Tyler, a teen she was babysitting (BabySUEtting).
- Sue has had six boyfriends thus far: Brad, Matt, Darrin, Jeremy, Tyler, and Aidan. For years, she has been romantically interested in Sean Donahue, but most people think they're like brother and sister - and that their relationship is platonic.
- She once tried out for cheerleading and, to her surprise, received a phone call informing her she made the team... only to find out the next day that the phone call had been a mistake.
- She had to wear headgear and, in fact, wore it to bed.
- She gets along better with Brick than she does with Axl, stating that she felt the two 'have a special connection'.
- She can be very naive and gullible.
- She likes waffles.
- She was born in a Leap Year, yet she has had two sixteenth birthdays, as her family floated her 2012 birthday (technically her 4th birthday) to 2013.
- She goes to college at East Indiana State.
- Her phone password is "Sue Heck Wins."
- She has a crush on Sean, but she doesn't think he likes her back.
- When she was little, her mom made an arrangement with the nurse's office at school so that she could call Frankie everyday at 10. She also did not participate in Brownies unless Frankie was the leader.
- Sue and Sean had their first kiss at the Heck's backyard.