Kataoka is a tall girl with long light brown hair that is kept in a ponytail with straight bangs. She is described as being "dashing" by Nagisa and according to Irina's fashion reviews of the students, she also has the physique and making of a model. This combined with her personality and talents earned her the title "Ikemegu".
Kataoka is a kind and capable person with very strong leadership skills which has been noted several times in the series. She's level-headed and rational and as a result is good at keeping everyone (namely the boys) in line. She was said to know how to take care of others, however, in the past, she allowed others to rely on her too much. A running gag is that she seems to have a relationship complex and seems to be greatly concerned about not being feminine enough.
During her arc, it was revealed that Kataoka was indeed dropped to Class E because of low grades. Her former classmate Kokona Tagawa made her help her study before every test, due to the claim that it's because Megu didn't teach her how to swim properly (when in reality it was Kokona's own fault for not taking more lessons) which nearly caused her to drown at the beach. Because she was constantly helping Kokona her own grades in her weak subjects became worse.
She was first introduced as the female class representative of Class E. Her spotlight moment in Chapter 43, when the class was swimming in the pool made by Korosensei. Her excellent swimming skill was when she saved Kayano from drowning. The reason for her low grades, which prompted her entrance to Class E were explained in the subsequent chapter. With Korosensei's guidance, they helped Tagawa to overcome her lackluster swimming, which caused her to not rely on Kataoka anymore. This experience helped Kataoka to learn not to let others rely on her too much.
She was shown to lead Class E in most times throughout different chapters. Notable examples include leading the girls and Nagisa through the bar room in the Assassination Island arc and later leading the rescue team during the God of Death arc.
Leadership: Being the female class representative, Kataoka occasionally takes charge of the class along with Yuma Isogai.
Athletics: Kataoka is the best swimmer in Class E. She was the representative of the school's freestyle before dropping to class E and recently swam 50 meters in 26.08 seconds. Karasuma notes that her athleticism allows her to carry the same momentum and constitution as the other male students of Class E, making her a competent opponent at close combat.
- Main article: Yuma Isogai
Isogai and Kataoka are fellow class representatives, often considered the leaders of Class 3-E. They often work together and are also shown to have a good friendship. Although their relationship is mostly work based, the rest of the class rumors about its true nature.
Kataoka gave Isogai a large bag of retail chocolates on Valentine's Day and revealed she planned to attend the same high school as his.
- Main article: Tōka Yada
According to the official character book, Yada had a crush on her, but it has since ended.
- Main article: Hinata Okano
Okano is her closest friend. They often spend their time off school together and share a worry about not being feminine enough. 
- Main article: Hinano Kurahashi
Kataoka and Kurahashi are shown to have a good friendship and are frequently seen together. The character book states that they get along well since their personalities balance each other nicely, and as a result they work well as a team.
(To the boys after their perverted plan is discovered) "Wherever you do or don't, it's clear you're all involved in this disgusting scheme."
- The name Meg means "Pearl" in English.
- Meg's surname Kataoka means "single, piece" (片) (kata) and "ridge, hill" (岡) (oka).
- Meg's best subject is Japanese while her worst subject is History.
- Her hobby/special skill is swimming.
- Her past club before joining Class E was Swimming Club.
- Her favorite food is a breakfast from hotel room services.
- She wants to become a flight attendant in the future. She's been trying to aim for more feminine professions as time passed.
- It was stated in her profile that her dream is to be carried like a princess, however she's always misunderstood when she tells others that and they assume she wants to do the carrying.
- Her most treasured possession are love letters she has received from boys.
- She picks out her older brother's clothes for him.
- She was called "Dignified Didact" during class 3-E training using code names. Her codename was written by Okajima.
- She is the tallest female student in Class E.
- Kataoka can be considered a foil to Nagisa in terms of physical abilities due her constitution and stamina being likened to that of a boy's where as Nagisa's is like that of a girl.
- In the "Girls you're interested in" ranking made by the boys on Chapter 19, she was ranked 4th, tied with Kayano. It's not shown what was written as her best point in the manga. In the anime, the comment next to her vote tally said "Dependable; straight bangs"
- During the Civil War, she and Takebayashi were both eliminated when Chiba and Hayami sniped them.
- In the tankobon extras, her statistics were listed as:
- Physical strength: 4.5
- Mobility: 4
- Close-range assassination: 4
- Long-range assassination: 2.5
- Academic ability: 4.5
- Characteristic skill: 4 (leadership)
- Her school rankings are:
- First Term Midterms: 72nd, 364 points
- First Term Finals: 7th, 475 points
- Second Term Midterms: 12th, 450 points
- Second Term Finals: 6th, 443 points
- Assassination Classroom Manga: Chapter 5, Cover
- Assassination Classroom Official Character Book: Roster Time
|Kunugigaoka Junior High School|
|Faculty||Korosensei • Tadaomi Karasuma • Irina Jelavić • Aguri Yukimura|
|Students||Masayoshi Kimura • Hinano Kurahashi • Yuma Isogai • Hinata Okano • Hiroto Maehara • Meg Kataoka • Kotaro Takebayashi • Toka Yada • Koki Mimura • Rio Nakamura • Nagisa Shiota • Kaede Kayano • Taisei Yoshida • Yukiko Kanzaki • Taiga Okajima • Rinka Hayami • Tomohito Sugino • Yuzuki Fuwa • Takuya Muramatsu • Kirara Hazama • Ryunosuke Chiba • Manami Okuda • Sosuke Sugaya • Sumire Hara • Ryōma Terasaka • Karma Akabane • Itona Horibe • Ritsu|
|Faculty||Gakuho Asano • Kiyoshi Terai|
|Students||Tomoya Seo • Teppei Araki • Natsuhiko Koyama • Ren Sakakibara • Gakushu Asano • Kaho Tsuchiya • Kazutaka Shindō • Kokona Tagawa • Nobuta Tanaka • Chousuke Takada|