Not now, Maria. It's Joaquín time.
Joaquín is a young man dressed in a blue uniform reminiscent of the uniform clothing from the Mexican Revolution. He bears brown epaulettes decorated with gold stars and gold strings. He wears two bandoliers around his chest and has many different medals covering his chest. He has white trouser pants and black knee high boots. He also wears a detachable black cape with blood-red lining and a sombero hat. He has a dual sword holder on his back which holster two silver and gold swords with a brown handle.
Joaquín has short brown hair, a very handsome mustache, and a goatee. He has an after shade shadow with a more worn wood texture. He has olive-fair skin with a wood texture that has silver joints in his points of articulation. He has wooden joints at his hips and knees. His eyes are hazel green or green with white highlight from the top of his cornea to the middle of his pupil. At the end of the film, he wears an eye patch.
Joaquín is a friendly, duty-driven, authoritative, and confident soldier. His greatest dream is to be a great hero like his father was. However, Joaquín can be very selfish as he sees himself as the greatest man to ever live, to the point where he starts putting his own ambitions before the feelings of his two best friends.
Though, Joaquín is not completely uncaring or self-centered. He than realize when his actions have gone too far or caused people sadness.
In The Book of Life
Joaquín is first seen in the movie as a young child with two of his best friends, Maria and Manolo. Both Manolo and Joaquín try to impress Maria to win her love, with Manolo playing his guitar while Joaquín relies on his strength, and persistence in becoming just like his father, Captain Mondragon. When Manolo and Maria are called by their fathers, Joaquín is left alone. He heads to his fathers' statue, and questions Manolo giving bread to La Muerte, disguised as a human. Joaquín then hears a noise from a building adjacent to the statue. When he enters the archway, he is greeted by Xibalba, who has disguised himself as an old man. He asks if he can have some bread, but Joaquín states that the bread is for his father. When he is offered a medal as a trade, he believes it's an old medal, but when Xibalba reveals that whoever wears the medal cannot be hurt, Joaquín accepts the trade, and hands over the bread. Xibalba warns Joaquín about a bandit that will stop at nothing to get the medal back. He realizes it could be Chakal, but when he looks for the old man, he is nowhere to be seen. Joaquín then is shown the next day refusing Marias request to free some pigs just because she does not like bacon. When a giant boar attacks Joaqiun, he attacks the boar back and doesn't get hurt due to his medal.
Like Manolo, Joaquín had a crush on and infatuation with Maria when they were young kids. He still remembers her as the three of them grow older and is stunned by her beauty upon seeing her again. Joaquín begins to see Maria as just another young woman, forgetting that Maria has a rebellious and independent personality and nature in favor of how he sees a mortal woman who just worships him. However, when Joaquín realizes and sees that Maria had only agreed to his marriage proposal in the first place in order for him to remain in San Angel in order to protect the town of San Angel from Chakal and his army of banditos, because Maria's father General Posada was pressuring his daughter Maria to agree to Joaquín’s marriage proposal in order for Joaquín to stay. Maria is deeply, truly, genuinely heartbroken when she learns and hears of Manolo's death, Maria agrees to marry Joaquín in great sorrow since she would only ever truly love Manolo, Joaquín begins to realize Maria's love for Manolo. Joaquín realizes that he is being very selfish for putting his own happiness and joy before Maria's.
Manolo and Joaquín have been best friends since they were young boys. Joaquín does understand that Manolo lives under the great shadow of his family of bullfighters and sympathises because he, himself, feels the pressure of living in his late-father's shadow. Their friendship has shown to remain strong throughout their lives. While Joaquín was learning to march he briefly stopped to wave hello to 'Manny', and when they were young adults, he stopped his crusade of fighting bandits to see Manolo's first bullfight.
But Joaquín's friendship seems to end at their mutual understanding. Joaquín uses every advantage he has to gain Maria's love and heart, even when he sees her smiling as Manolo sings for her. Instead of talking to Maria immediately afterwards Joaquín goes and instead talks to her father General Posada to get his permission to marry Maria without Maria's knowledge and get her to marry him. He fights (almost) with Manolo when the two of them point out the other's family issues and storms out of Maria' grand welcome back party afterwards.
Later when he sees his best friend carrying back Maria's (comatose) body, Joaquín angrily blames Manolo saying her death was completely his fault. Even going so far as to say it should have been Manolo who had died instead of Maria. Joaquín shows some sadness when he tells an awakened Maria that Manolo is dead. The death of his best friend Manolo is somewhat the catalyst to Joaquín realizing that his very selfish actions have caused terrible unhappiness onto his two best friends.
When Manolo returns, Joaquín remains in the fight and battle against Chakal and his army of banditos by aiding Manolo and Maria. Joaquín even secretly sneaks the Medal of Everlasting Life unto his best friend Manolo at his own expense to ensure he will come out alive.
- Joaquín is loosely based on Jorge's childhood friend, Mauricio, who died when he was nine. His death led Jorge's mother to teach him about Día de los Muertos and the rest of its history. There is a dedication in Spanish to him at the end of the credits.
- Joaquín is truly known to be Joaquín Jr., because his father was named as Joaquín Mondragon Sr., according to animator and director Jorge R. Gutierrez on his Twitter webpage account.
- Joaquín's mare's name is Plata. He got her as a gift from his father as a graduation present from the academy.
- Joaquín's artistic talent is calligraphy, as told by Gutierrez on his Twitter webpage account again.
- After war hero Captain Mondragon's death at the hands of the bandit king Chakal, Joaquín Jr.'s mother, Gertrude Mondragon, left the town of San Ángel, leaving her only son in the care of General Posada.
- Gutierrez's Twitter page implied that Joaquín formerly lived in the Mondragon mansion.
- Joaquin's rank in the military was Private First Class.
- Joaquin is the best dancer between himself, Manolo, and Maria.
- Joaquin is related to Frida Suarez from "El Tigre". 
- Joaquin was originally going to die in the bandit raid, crushed by his dads statue, which would have been the moment he gave Manolo the Medal of Everlasting Life.