Brilliant, but Lazy: To such levels that in a Volume 6 strip Kagami was unsurprised at the prospect of Konata getting into Tokyo University just because it's close to Akihabara (of course, she didn't get into so prestigious a university as Tokyo U).
Older Than She Looks: At seventeen (later eighteen) years of age, she only stands at 142cm (4'8"). Not really annoyed by that though.
One of the Kids: She's ecstatic at turning eighteen allowing her to buy H-Games without having to go through her dad, but still pretends to be a prepubescent kid (and can pull it off successfully) to get cheaper movie tickets... and that's among the least immature things she has done as an eighteen-year-old...
In her birthday arc in Volume 7, she admitted she has "eighth grade syndrome". Wrong Genre Savvy sets in once one realizes that this Japanese slang can be applied to actual eighth-graders, and with connotations of Emo with a taste for Melodrama. That being said, anyone older than eighth grade who has it probably qualifies for this trope.
Otaku Surrogate: In a series full of otakus, she stands out the most by virtue of having "male otaku" traits.
One strip lampshaded that, saying she is only biologically female.
Yuri Fangirl: She watches Strawberry Panic!, and bought some of Hiyori's Minami/Yutaka doujinshi at Comiket, although she's initially unaware that the latter was based on her otherwise innocent cousin.
Konata's closest friend and Tsukasa's older twin sister. She is easily angered by some of Konata's more... "playful" antics, but always seems to be the one who understands her hobbies. Her liking of light novels is also a driver of plot.
Muggle: She plays this role in terms of otaku culture, although her prejudice in that is relatively minor. Her criticism is more concentrated in Konata's Dirty Old Man antics, irresponsible spending, laziness in studies, and the lack of a real-life goal.
Tsundere: Her deredere side is not about romance but more on loneliness in general. Her Image Songs even have this — one is fast and upbeat, the other a bit slow and has lyrics hinting at her loneliness.
Episode 10's "Lucky Channel" discusses at length whether "tsundere" is the right word to describe her.
Tsurime Eyes: The most significant feature to distinguish her from Tsukasa.
Captain Ersatz: Of Akari Kamigishi of To Heart, at least when it comes to character designs. Lampshaded at least twice in the anime — when Konata gives her a school uniform for a birthday gift (Kagami is instantly reminded of To Heart), and when she was noticed by some otakus who call her Akira and how they ask her to say "Hiroyuki-chan".
Foil: She often serves as this to Konata and Kagami.
Highlighted in the anime when Konata asks the twins their favorite colors (white for Tsukasa, black for Kagaminote in the manga it's violet) and when Kagami asks the other two how they reacted to a manga scene (Konata laughed, Tsukasa cried; however both answer "Sgt. Frog" when asked about their favorite manga, prompting Kagami to wonder: "Are you the same or different?").
Heavy Sleeper: She wakes up at noon, sometimes later, and still thinks it's morning until someone points it out to her.
Idiots Cannot Catch Colds: Kagami says she always seems to be fine when everyone else is laid up, which Konata calls "inconspicuous"...
The Ingenue: A lesser degree of this trope when compared to Yutaka below.
Miko: When her father is the local shrine's priest...
Nice Girl: The official guide lists "Good Person" as her highest stat. One strip also shows that her idea of an April Fool's joke is lying about lying.
Afraid of Doctors: Miyuki is afraid of going to the dentist, and often tries avoiding this even when she knows she should go.
Beware the Nice Ones: Occasionally; one Volume 4 strip has Konata telling her that she and the other girls won't blindly follow orders. When she replies with a smile that she'll entertain other opinions, even Kuroi-sensei freaks out, implying she's willing to pretend to hear them out so long as ultimately she calls the shots. She's that assertive... she's just too polite to be blunt about it.
Hot Teacher: As of manga volume 8, she's doing work as a home-tutor.
Huge Schoolgirl: She isn't really very tall (see group shot above) — she's only slightly taller than the Hiiragis and is slightly shorter than Patty. She just spends a lot of time with the diminutive Konata.
Yui assumes Miyuki to be unusually tall because her family's genetic shortness gave her a rather skewed perception of what average height is.
Broken Bird: Averted. In Volume 4 Chapter 118, it was revealed that Yui's sisterly love helped her avert problems in social interactions resulting from the years she spent as an Ill Girl.
Captain Ersatz: Of Chiyo Mihama of Azumanga Daioh. This was lampshaded when she introduced herself in front of the class (pictured above), and further lampshaded when she found she unwittingly shouted out to Chiyo, because "[Konata]'s geekiness is rubbing off on me!"
Cute Clumsy Girl: Konata observed she has that same "cute shortcoming" as Miyuki.
Cutesy Dwarf: In-universe assumption of some of her classmates towards her, which is not particularly surprising in light of her associated tropes. She isn't really comfortable about this.
The Ditz: Of a much lesser magnitude compared to Tsukasa though.
Don't You Dare Pity Me!: She, surprisingly, has moments of this, especially a Volume 7 strip where, hearing that Minami has been helping her to the latter's detriment in PE, she harshly asked Minami to not help in a long-distance running match.
Entering the story by returning Yutaka's handkerchief in the beginning of what can be seen as a Romantic Two-Girl Friendship, Minami is a quiet, expressionless girl often misunderstood by others to be creepy. Good at most subjects, and is childhood friends with neighbour Miyuki since both of them love reading.
A-Cup Angst: She is completely flat-chested — at least Konata and Yutaka have very small ones. Her angsting over this is close to Once an Episode frequency.
Strips in Volume 4/5 show her making different yaoi/yuri fantasies about Setsubun, not to mention another about Konata kissing Miyuki, after the former said that tooth decay can be transmitted by kissing.
Kagami and Ayano's classmate for five consecutive years, Misao is the latter's childhood friend and, as defined by the former, an unorganized "lazy ass". A recurring theme in post-anime strips is her rivalry with Konata — for Kagami, even Misao considered Kagami as being cold-hearted. Later, she got into the same program of the same college as Konata.
First appearing in Volume 4, Kō is the president of the Animation Research Club and Hiyori's "boss" on the club's periodicals. She's the only 11th grader in the series. Does not appear in the anime, but she did appear in the Net Idol Meister video game.
Challenge Gamer: One of the running joke about her is her trying to beat Konata on arcade fighting games.
Gamer Chick: Her otaku tendencies are mainly in gaming and less on manga — that doesn't mean she does not care about manga anyway.
While she doesn't appear often in the manga, she gets introduced with Ko often. She's a close friend of Kō, and in the visual novels gets possessed by an alien at one point and even has some leftover powers remaining.
Class Representative of Hiyori's class who appears in Volume 7. She is also an otaku, but tries to hide it as she is an upper-class girl who is class president. However, she runs into Hiyori on one of her shopping trips to Comiket, who discovers her secret. She is good at home economics, but is bad at art. She likes "cute" things and likes sweets, as well as coffee and milk.
Konata, Tsukasa and Miyuki's homeroom teacher, and world history teacher for all the seniors. Has lots of free time to play video games and watch baseball games. Still believes in the power of corporal punishment.
Parental Hypocrisy: She plays the same online game as Konata, and has been into MMORPG's since before she was Konata's age, but she tells Konata off for doing that very thing, and uses in-game chat to remind her to do her homework. When Konata calls her out on this, she remarks that, as a teacher, she has a duty to uphold, which Konata accepts as understandable, but still...
Konata's cousin and Yutaka's older sister. She works as a traffic cop, but even Konata wonders why can she keep at that position. Surprisingly, she showed real care towards Yutaka. Has an offscreen husband.
Bunny-Ears Lawyer: You usually don't want your police officers to be nonsensical goofballs.
Beauty Mark: On the outer corner on his left eye. Such a mark customarily symbolizes sadness, which is appropriate for him; he really misses his late wife Kanata.
Bumbling Dad: He's certainly not stupid or lazy, yet the entire Izumi-Kobayakawa household thinks so.
Cassandra Truth: Nobody believes that he is actually a hardworking writer who can write wholesome, non-otaku-related topics, has quite a bit of book smarts, has had a relationship with Kanata that was far beyond lolicon, so on and so forth.
Doting Parent: Someone's got to give the guy credit for being an attentive and loving father who raised a happy and emotionally well-adjusted daughter to adulthood... eccentricities notwithstanding.
Fan Nickname: "Awesome-kun", for having what is considered to be the epitome of an otaku's dream life (well, leaving aside his dead wife,) as well as having a daughter who appreciates and emulates his hobbies.
Lolicon: He buys H-games for his underage daughter and takes shots of nubile girls at other schools' sports festivals. Needless to say, even his daughter was fed up and frequently fears for his arrest.
In later volumes of the manga this aspect of his gets subdued. One Volume 7 strip has Yutaka catching him looking between the legs of figurines — which horrified the innocent girl to no end. This ends up becoming a running gag.
Unfortunate Implications: In-universe — the figure incident could be seen as him actually having dropped it and picking it up. Also, in volume 7 he gets spotted by Yutaka pantsless while trying to find toilet paper. Konata hears a scream and assumes he did something stupid.
Younger Than He Looks: Even as a teenager he looked way older than Kanata, who turns out to be a bit older than him.
Jerkass: Occasionally acts like a mild-grade variant; for instance she's been known to forget to wake up Tsukasa, then tell her youngest sister that she (Tsukasa) slept through the wake-up call. At one point Kagami asks her, "Is avoiding your troubles all you do?"
Jerk with a Heart of Gold: While both she and Kagami verbally spat multiple times during the time she made paella, Matsuri also made sure to give Kagami credit for buying the ingredients when their parents praised Matsuri for making it.
An anime-only character, he is the manager of the Animate store Konata frequents. He is actually the mascot for the Animate chain as Captain Animate, created by Shimamoto Kazuhiko in the late 90s; but the one who made him known in Japan was none than Hideaki Anno who directed a short Original Video Animation for the character, a Radio Show was also made. Anisawa was made to help boost the sales and pick interest of the general public into buying anime merchandise, not just for Animate stores.
Art Shift: He and his store's staff are all drawn in a distinct Shounen art style with a different color palette from the rest of the characters.
Ass Kicking Pose: Episode 12, when he lectured a salesman about the value of leftover merchandise.
Product Placement: The Animate chain does have commercial links with this series, judging from the existence of some of its strips from its in-store magazine.
Shout Out: In one episode, he pulls a freaking Geass from out of nowhere. Lelouch's Geass. He uses it on Konata to get her to FINALLY buy something in his store... only for it to turn out that she doesn't have enough money.
Spooky Photographs: She unintentionally caused one of these while trying to get a family picture with her husband and daughter. The sight of her ghostly figure in the photo causes Konata and Soujirou to freak out.
An Idol Singer in the Lucky Star universe and "navigator" of Lucky Channel. She's fourteen — younger than most of the cast — but has eleven years of acting experience. In Comptiq she is the name in which the magazine reply readers' mail.
Ascended Meme: "Wa-wa-wa-wasuremono~" Upgraded to an ending in Episode 13, and a full song when the album came out.
Beware the Nice Ones: He takes an astounding nineteen episodes' worth of physical and emotional abuse from Akira, but when he finally snaps the results are epic. He even provides the image for the trope page.