- “Crying helps me slow down and obsess over the weight of life's problems.”
- ―Sadness to Joy
Sadness came into existence after Riley's first 33 seconds of her life; there, she met Joy. When she caused baby Riley to cry, Joy pushed her aside and fixed the situation. Sadness was only used whenever Riley threw tantrums or did not get her way.
- None of the other Emotions really understand what Sadness' role is. Sadness would love to be more optimistic and helpful in keeping Riley happy, but she finds it so hard to be positive. Sometimes it seems like the best thing to do is just lie on the floor and have a good cry.
Sadness is literally the very definition and being of sorrow and gloom. She is hardly ever used because Joy is the boss and doesn't want Riley to ever be sad, even when she needs to be. Because of this, Joy treats Sadness badly. Secretly, however, Sadness yearns to earn her place among the other emotions, even though the others do not believe Sadness has a purpose in the mind and almost always prevent her from trying. She is the most sensitive out of all the emotions, as she felt genuinely hurt by Joy's abandonment because "Riley needs to be happy", which made poor Sadness feel she was truly useless and unneeded.
Sadness also complains a lot, as seen when she keeps saying she's too sad to walk or do anything, much to Joy's frustration, because due to being obese, that means pulling her by her chubby leg.
Sadness is also smarter, has more common sense, and is more pragmatic than the others, which proved expedient in the journey through Riley's mind, as she kept trying to warn Joy about the dangers of taking Bing Bong's "shortcut" through Abstract Thought, which was really a dangerous place to go through, but nobody listened to her. She also suggested scaring Riley to wake her up, but Joy thought that giving her a fun dream would wake her up, which it wouldn't.
Despite her pessimistic disposition, sarcastic demeanor and being negative virtually all the time, she is very considerate and compassionate towards others; when Bing Bong was sad about losing his wagon, she sympathized with him and let him tell his true feelings, which made him feel much better. Unknowingly, this is because of Sadness' true purpose - her role is to tell others when Riley needs help by helping her let the sadness out so she can then let it go. When Sadness is requested to take control after Riley's sorrow became evident, she is able to let Riley express her true feelings and helps Riley find happiness at last. After the other emotions finally trust and accept Sadness, not only does Joy start treating her better but Sadness gains more confidence in herself as well, now that she has finally found her place.
Despite her personality, Sadness is actually a fan of romance-related things. This can be seen when she smiles when she sees the Imaginary Boyfriend, and Tragic Vampire Romance Island. This appears to be one of the few things that make her happy.
Sadness first appears at Riley's birth. She appears less than a minute (33 seconds to be exact) after Riley's first emotion, Joy, presses a button that makes baby Riley smile. Sadness makes Riley cry, but Joy pushes Sadness out of the way and makes Riley happy again. Due to Joy's obsession since then with keeping Riley happy, she treats Sadness poorly. As a matter of fact, the other emotions tend to exclude Sadness as well. They won't let Sadness take the wheel at all, no matter how sad the situation needs to be.
When Riley moves to San Francisco, everything starts to go from bad to worse; Riley's dad doesn't have time for her, their new house is terrible, they only serve broccoli pizza and the moving van won't come for weeks. Sadness thinks this is a good time for her to handle Riley's problems, but Joy still didn't let her.
The next day at Riley's new school, Joy tells Sadness to stay out of everything and stay in a small white circle Joy made of chalk, so Riley won't be sad. When Riley is called up to introduce herself, she talks about the good old days in Minnesota and starts to cry because she misses it. It is revealed that Sadness was touching a memory that was originally positive and she made a new Core Memory that is a sad one. The other emotions begin to panic as the sad core memory rolls into the core memory chamber. Joy immediately takes the core memory out and decides to throw it away. Sadness tries to stop Joy, but it causes them and the core memories to be accidentally sucked up into a tube and they end up in Long Term Memory. Joy decides to find a way to get back to Headquarters with Sadness as her guide.
During the long journey, they run into Riley's old imaginary friend from toddlerhood, Bing Bong, who knows a way back to Headquarters. Joy decides to have him show them the way back. While on their way back, they go through Imagination Land, where they see that many of the childish aspects of Riley's personality are being removed, including Bing Bong's rocket that is sent down to the Memory Dump. Bing Bong starts crying and Joy tries to get him to stop by being goofy, but it doesn't work at all. Instead of trying to cheer him up, Sadness decides to sympathize with him and let him express his emotions. In just a minute or so, Bing Bong feels better. Joy is shocked that Sadness could solve Bing Bong's problems without cheering him up.
The next day, the trio finds out that Riley is running away and that all the personality islands are disappearing one by one. Joy decides to leave Sadness behind and return to HQ, but her plan backfires when she falls into the Memory Dump and Bing Bong comes after her. When Joy looks at all of the forgotten memories, she sees tons of sad ones and realizes that Riley's problems were solved because Sadness was the one in control during those times and Joy finally sees that she went way overboard with trying to keep Riley happy. Joy makes it out of the chasm, but Bing Bong sacrifices himself and fades into oblivion. Joy tries to get Sadness to come back with her, but Sadness thinks Riley doesn't need her and just cries her eyes out and runs away from Joy. Soon enough, Joy is flung into the air and grabs Sadness and the two make it back to HQ, just as Riley is about to run away. The others tell Joy to handle Riley's problem, but Joy tells that it's now up to Sadness to save Riley. After Sadness successfully removes the idea, the console becomes operative again. Joy then hands the core memories to Sadness, who turns them all sad and places them in the core memory holder. At first, Sadness is unsure and nervous because she has never done this before, but Joy assures her otherwise. Riley comes home and the sad memories help her tell her parents how she really feels about her new life in San Francisco and that she misses Minnesota.
Just then, a new core memory materializes - it's both yellow and blue (which creates Melancholy), creating a bigger, cooler, greater and updated Family Island. Joy and Sadness hold hands on the new core memory and, when Riley turns 12, they finally become a team and the best of friends.
Sadness and the other emotions appear in this new short, where they help Riley when her friend, Jordan (a boy Riley met at the end of the film) comes over for a visit.
Sadness appears in Disney INFINITY's third installment as a playable character.
Joy and Sadness have a meet-n-greet area near the Art of Animation exhibitions at Hong Kong Disneyland for a limited time during the coolest summer ever event in 2015. They are currently the only Inside Out characters to appear at Disney Parks. Inside Out characters will be at Epcot with Baymax soon.
- According to Pete Docter, her appearance is based on that of a teardrop.
- Sadness could resemble a nerd, with her thinking she doesn't fit in, being fat, and with her big round glasses and sweater.
- Even though Sadness is mostly seen as mournful, there are several occasions when she is seen smiling, proving that emotions can express more feelings than their own representation.
- In the "Meet Phyllis Smith" video, there is a scene where Sadness fell flat on Anger's face.
- Sadness is the sixth female deuteragonist of Pixar. The other five are the Princess Atta of A Bug's Life, Dory from Finding Nemo, Helen Parr from The Incredibles, EVE from WALL-E and Queen Elinor from Brave.
- Sadness is the only emotion that wears a head accessory, that being her glasses.
- In an early draft for the film, Sadness wasn't originally going to get lost with Joy in Riley's mind, but instead, her role would have been given to Fear.
- Phyllis Smith, Sadness' voice actress, was chosen for the role after Jonas Rivera, Inside Out's producer, noticed her performance in the 2011 film Bad Teacher.
- Sadness is a fan of tragic romance stories and points to Tragic Vampire Romance Island as her personal favorite.
- Sadness' personality is similar to that of Eeyore from the Winnie the Pooh franchise.