Main characters: The Mario Brothers | Allies | The Koopa Kingdom (Bowser — Bowser Jr. — The Koopalings — Other High-Ranking Subordinates — Bosses) | Assorted Nasties
RPG characters: Super Mario RPG | Paper Mario (64 — The Thousand-Year Door — Super — Sticker Star — Color Splash — The Origami King) | Mario & Luigi (Minion Quest: The Search for Bowser)
Spinoff series: Yoshi's Island | Luigi's Mansion | Mario Golf | Mario Tennis | Super Mario Maker | Donkey Kong series (Kongs) | Wario series (Wario and Waluigi)
Crossovers: Punch-Out!! | Super Smash Bros. | Mario and Sonic at the Olympic Games | Skylanders | Mario + Rabbids Kingdom Battle
Other media: Super Mario Bros. (1993) | The Super Mario Bros. Movie
BillyA professionally ranked golfer, and the hardest character to beat in the game.
MarkAn amateur golfer that can be challenged in match play.
- Regional Bonus: Only appears in the NA version of the game.
SteveA beginner ranked golfer. The player can play against him in the "bet on 1 hole" mode if they have $500, as well as challenge him in match play.
- Regional Bonus: Only appears in the NA version, but unlike Mark, is the only character within the game to not make an appearance in any Japanese-released game.
- Shout-Out: His name may be a reference to Steve Miles, one of two men who localized the game for the NA market.
TonyA semi-professional ranked golfer, and the second-hardest character to beat after Billy.
PlumOne of the first playable golfers in the game, and a generally well-balanced golfer.
- Adaptation Dye-Job: Perhaps due to color limitations, she has red hair instead of brown when she appears in the GBC version.
- Ms. Exposition: She explains what terms mean in the golf glossary.
- Previous Player-Character Cameo: Only playable in the N64 game, but shows up to explain terms to the player in the GBC version. She also makes appearances in Super Smash Bros. Melee and Brawl, as a trophy and sticker, respectively.
- "Silly Me" Gesture: Her Bogey animation has her hit her head softly with her hand and look at the camera.
CharlieA teenager who is possibly trying to become a great golfer, similar to Plum. He is also a starting character along with Peach, Plum, and Baby Mario.
A bright and happy golfer, Sonny is very talented and sticks to a traditional play style.
- Secret Character: Unlocked by beating him in 3rd Match of the Get Character mode.
- Signature Headgear: Sonny always has his fedora with him. He only removes when he scores a Bogey or lower, where he hangs it in shame, or an Eagle or higher, where he enthusiastically throws it in celebration.
HarryTotally confident in his play, Harry's philosophy is "If I play my best game, I'll win!"
- Secret Character: He's unlocked by beating him in 5th Match of the Get Character mode.
MapleAn energetic gal considered the best female player in the circuit.
- Secret Character: She's unlocked by earning 50 Birdie Badges in Tournament Mode.
KidOne of the four playable characters of the game, an unlockable character in Mobile Golf, and the coach of the player in Advance Tour. Becomes the Links Singles and Doubles champion in Advance Tour as well.
- Ascended Extra: He's the only Mario Golf character not related to the main Super Mario series to become a Spirit in Super Smash Bros. Ultimate.
- Career-Ending Injury: In the five years between the original game and Advance Tour, he trained so excessively that his muscles were too strained to even pick up a golf club. However, he does finish recovering in the latter game, and returns to playing.
- Child Prodigy: He had apparently started playing golf ever since he was three, and had already become a golfing prodigy at age ten.
- Cutting Off the Branches: Advance Tour states that he was the one to become Grand Champion.
- Inconsistent Coloring: In 64, he has dark skin. But all artwork for him has lighter skin.
- No Celebrities Were Harmed: He's clearly inspired by Tiger Woods.
JoeOne of the four playable characters. Becomes the Marion Singles and Doubles champion in Advance Tour.
- Disco Dan: His whole persona is that he's cool, but a little bit out-of-date. Even was a professional disco dancer before his golf days.
SherryOne of the four playable characters. Becomes the Palms Singles and Doubles champion in Advance Tour.
AzaleaOne of the four playable characters. Becomes the Dunes Singles and Doubles champion in Advance Tour.
- Expy: It's heavily speculated that she was meant to be a stand-in for Daisy.
- Expy Coexistence: Subverted; She's playable in Advance Tour, and Daisy is playable in Toadstool Tour, but the two never appear together.
Gene YussAn elite golfer that appears suave, intelligent, and sophisticated, though arrogant and self-absorbed. The Links champion in the original game, Doubles champion alongside Kid in Advance Tour.
- Punny Name: His name sounds like "genius".
- Red Baron: He's known as the Birdie King and the Greatest of the Great.
- Third-Person Person: In Advance Tour, he refers to himself as "the Gene".
GraceA former prodigy from a young age, she was once known as the Princess of Golf, and was the Palms champion in the original game, Doubles champion alongside Sherry in Advance Tour.
- Meaningful Name: She's certainly one of the most graceful cast members.
- Red Baron: She's called "The Princess of Golf".
PuttsFormer champion of the Marion course. Becomes Doubles champion alongside Joe in Advance Tour.
- Ironic Nickname: He is abysmal at putting, and bang-average at anything else.
TinyChampion of the Dunes course, before being defeated by Azalea. Becomes Doubles champion alongside her in Advance Tour.
Napple (ナップル Nappuru)A cute little girl, if not competitive and spoiled. She constantly practices to improve her golfing skill and prowess, and is a quick learner.
BeanA rowdy, childish boy who was raised on the ranch. There, he not only does his daily deeds as a cowboy, but he practices golf as well. He is the champion of the first tournament that the player must defeat in singles.
NeilThe male player character.
EllaThe female player character.
BuzzThe male rival.
HelenThe female rival.
- Ms. Exposition: She explains what terms mean in the glossary.