He is Bolin's older brother and the captain of the Fire Ferrets, of which both Korra and Bolin are members. He is their firebender. When Korra first joins, he isn't very impressed with her even though she is the Avatar but admits she has skill after she helps them win a match.
He is also a member of the new Team Avatar, which also consists of Korra, Asami, and Bolin.
He falls for Asami when she accidentally runs him over and they begin dating. However Korra also has feelings for him while Bolin had a crush on her. Korra tried to confess her feelings for him and they share a kiss, which Bolin sees, devastating him, though he gets over it.
When Korra is kidnapped by Tarrlok, Mako goes overboard to save her, which gets Asami concerned. When Korra escapes Amon who took away Tarrlok's bending, Naga brings her to Republic City and Mako carries her bridal style to get her to recover. Asami becomes suspicious of Mako's feelings for Korra.
Once Republic City is under siege by the Equalists, Team Avatar hides at the Air Temple. Bolin accidentally tells Asami about Mako kissing Korra. She confronts him and says they might not be in a relationship after the siege is over. Despite this, she still likes Korra and was only hostile to Mako. They break up but not only do Mako and Asami stay friends, but Asami remains loyal to team Avatar, even battling her father again and defeating him with Bolin's help. When Korra decides to finally confront Amon, he insists on coming along and they both find Tarrlok in an attic. He tells the two that Amon is his brother and is using bloodbending, not energybending to take away a person's bending. The two enter the arena and save Tenzin and his children, preventing airbending from being erased from the planet. Amon bloodbends both of them and uses his bloodbending to remove Korra's bending. Angered, Mako resists Amon's bloodbending and hits him with electricity, sending him flying into a wall. Mako then carries Korra to escape only to be bloodbent again. Before Amon can remove Mako's firebending. Korra's love for Mako helps her finally learn airbending, which knocks Amon into the water. He then waterbends into a cyclone, only to learn the Equalists saw him.
Mako comforts Korra after Katara is unable to restore Korra's bending and he finally confesses that he loves her. Korra is unable to respond and runs off only to finally get wisdom from Aang, who restores her powers and enables her to undo Amon's work. Korra confesses she loves him too and they have their second kiss.
Mako is a very skilled firebender, and is able to control his emotions, allowing him to use electricity. Even Amon admitted Mako was very skilled to resist his bloodbending.
- Mako is voiced by David Faustino, who is famous for his role of Bud Bundy on the hit sitcom, Married With Children. He is also well known for voicing Helia in the nickelodeon version of the Winx Club.