Luigi is Mario's younger brother in the Super Mario games. He often helps him out on his missions to stop Bowser from whatever he's doing, whether it be kidnapping Princess Peach or winning a tennis match. He is a very popular character and is famous for having a lot more personality than his brother. He is nice, funny, sometimes heroic, and sometimes cowardly. He is also afraid of ghosts.
Luigi dresses similar to his brother- but instead of red, however, Luigi has a green hat and undershirt along with his blue overalls. He also sports brown shoes, like his brother. He used to be just a green palate swap of Mario, and his name is based off of the Japanese word for 'similar.' Luigi is a bit taller and thinner than Mario. Also, his initial "L" is on his hat. He has a black mustache, too. His girlfriend is Princess Daisy, and there is a theory that he and Princess Peach are Princess Rosalina's parents. He has a dog named Polterpup, and works with Professor Elvin Gadd in their mansion. He has a meme based off of him, called Weegee, and he has been in the news before because of the Luigi Death Stare, which is an easter egg in Mario Kart 8. He has been the main character in a few games, including Mario is Missing!, Luigi's Mansion, Luigi's Mansion: Dark Moon, Luigi Mansion Arcade, and New Super Luigi U.
Top Speed +2, Weight +6.
Mario Bros. was the first game that Luigi appeared in. In it, he is simply just a green palate swap of Mario. He has the same controls and abilities as him. Luigi is probably portrayed as a coward today because in the commercial for the Atari 2600 version of Mario Bros., he was portrayed as a coward.
Super Mario Bros.
In Super Mario Bros., Luigi is only playable in 2-player mode. He controls exactly the same as Mario, and has the same jumping power, traction, and and running speed. He was still just a palate swap of Mario. In Super Mario Bros.: The Lost Levels, players could either chose a Luigi game or a Mario game. In the Luigi game, he was faster, jumped higher, and had worse traction. The Luigi Game is sometimes considered to be the Hard Mode of the game. In Super Mario Bros. 2, Luigi was based off of a character from the original Doki Doki Panic, Mama. Like her, he had a very high, floaty jump. He was also pretty fast, but not as fast as Toad. In Super Mario Bros. 3, Luigi is only available in two-player mode, like he was in Super Mario Bros. However, he can use more items and pick things up.
Super Mario World series
In Super Mario World, Luigi gained the ability to Spin Jump. In the Game Boy Advance port, he gained a few extra abilities that Mario didn't have, and Yoshis that he rode also gained abilities. However, he did not appear in Super Mario World 2: Yoshi's Island.
Super Mario 64 series
In Super Mario 64, there were myths about Luigi being in the game. 'Screenshots' of him in Super Mario 64 could be found online. One fake way to unlock him was getting 2401 coins. He was not in the game because the N64 couldn't handle it. However, he did appear in Super Mario 64 DS, where he can be unlocked by defeating King Boo and opening his door. He is the fastest swimmer in the game, has a fluttery jump, and spins slowly through the air after backflipping, which can lead to some shortcuts. He can also walk on water for a few seconds, but is slightly slower than Mario and has worse traction. He also cannot wall jump. Luigi did not appear in Super Mario Sunshine.
New Super Mario Bros. series
In New Super Mario Bros., after the credits end, players are given the code to unlock Luigi, L + R + A, which they have to type in before selecting a file. Then, they can play as Luigi, who pretty much controls the same as before. In New Super Mario Bros. 2, he is the second character in Co-Op Mode. His Tanooki form looks more like a fox than a racoon, like it looks in Super Mario 3D Land. He can be unlocked after defeating Bowser in World 6. Players have to press L + R while starting the game to play as him. In New Super Mario Bros. Wii, Luigi is one of the four playable characters. However, he can only be selected in a multi-player mode. He is also the Super Guide for levels where players died a lot. The catch is that he will not collect Star Coins while he is the Super Guide. In New Super Mario Bros. U, Luigi is available in any multi-player mode. In New Super Luigi U, Luigi is the main character, and is available in any mode. He runs faster, jumps higher, and has worse traction, as usual.
Super Mario Galaxy series
In Super Mario Galaxy, after players 100% complete the main game, they will unlock the Luigi game. They can switch between Luigi and Mario at any time, but have to complete every mission as Luigi and Mario to fully 100% complete the game. As usual, he runs faster, jumps higher, and has worse traction. Luigi can be rescued inn mission "Luigi and the Haunted Mansion" In Super Mario Galaxy 2, Luigi will sometimes appear in levels and will offer to complete the level for Mario. Players can accept and use him for the rest of the level. After Bowser's Galaxy Generator is completed, players can switch between Mario and Luigi at any time. Also, after a level is completed with Luigi, or players collect 9999 coins, ghosts of him will appear in levels. Luigi was most likely going to appear in Super Mario Galaxy 3, but it got cancelled.
Super Mario 3D Land/World series
In Super Mario 3D Land, Luigi can be unlocked after defeating the final level of Special World 1. He has a higher jump, runs faster, and has worse traction. He also looks more like a fox with a Tanooki leaf than a racoon. In Super Mario 3D World, he is one of the four main playable characters, and controls exactly the same as he does in the other 3D Mario games. He is also in the game's Luigi Bros. minigame.
Super Mario Maker
In Super Mario Maker, Luigi has a Mystery Mushroom costume. It can be unlocked by completing the 100-Mario challenge, or scanning a Luigi amiibo. It replaces some sound effects with sound effects from Luigi's Mansion.