Jean-Jacques Leroy (ジャン・ジャック・ルロワ Jan Jakku Rurowa), commonly referred to as JJ (his initials) by most people, is a character in Yuri!!! on Ice. He is a Canadian figure skater, the son of Alain Leroy and Nathalie Leroy and the fiance of Isabella Yang.
Jean-Jacques is a moderately tall, well-built and handsome tan-skinned young man with black hair that is styled in an undercut with bangs hanging on the left side, grayish-blue eyes and thick dark eyebrows.
He has several tattoos on his body:
- A maple leaf with a rose flower overlay on his right bicep and
- The last three lines of the Canadian national anthem written in cursive below.
- A stylized design with the initials JL in the center of his lower back.
- His left bicep features a tattoo of his JL initials.
During his short program, Jean-Jacques wears a lavender costume with shimmering purple embellishments.
During his free skate, Jean-Jacques wears a green costume with shimmering navy blue embellishments and a blue sash.
Jean-Jacques tends to run his mouth quite often, but is otherwise a very trustworthy person who consistently carries out any promises he makes.
He is also very confident, almost to the point of arrogance. During his short program, he thinks about how he is the only person who can pull off a collaboration with a world-famous band, and how he is the king.
Though Jean-Jacques is not above succumbing to pressure, he is shown to be headstrong, quickly recovering from pressure after the Grand Prix Final short program.
Jean-Jacques is a Canadian figure skater who comes from a family of figure skaters – his parents are former ice dancing Olympic champions, and his younger brother and sister both compete as Juniors. JJ started skating at the age of three. He previously trained in Colorado Springs with Leo as a junior and in Detroit under Celestino.
He is a prime candidate for both the GPF and Worlds gold.
Jean-Jacques relies on great height on jumps to clear quadruple and combination jumps, but he never does them late in the program so he can balance other elements of the program.
Alain is Jean-Jacques' father/trainer  who is very supportive of his son and caring more about Jean-Jacques' personal well-being than how well he performs in competition.
Nathalie is Jean-Jacques' mother/ice skating coach whom he confides in his mother in his time of weakness and Nathalie is always gentle and reassuring of him when they talk with each other.
Isabella is Jean-Jacques' fiancée whom he promises to marry after winning the World Championship and he thinks of her while skating at the Rostelecom Cup that he brings her with him to the Grand Prix Final. Isabella is also a member of his fanclub called the JJ Girls. Unfortunately, the pressure of his promise to marry her after winning proved too much as JJ suffered the worst short program score in his senior career during the Grand Prix Finals, much like how Yuuri Katsuki failed in the previous season.
Due to JJ's strong Christian background, he is against pre-marital sex and their relationship is pure.
Jean-Jacques regards Victor as an adversary obstructing his path to the top. In the previous season, Jean-Jacques composed his free program specifically with the goal to prevent Victor winning gold in the GPF, but was surprised when Victor dropped out to coach Yuuri. Victor, on the other hand, does not think much of Jean-Jacques, preferring not to converse with him at all.
Jean-Jacques likes to irritate Yuri, calling him first a lady and then Yuri-chan later. He also asks Yuri to cheer him on at the Rostelecom Cup free skate, much to Yuri's annoyance. He has no ill feelings towards the younger skater and praises Yuri at being popular with the Yuri Angels.
At Skate Canada, Jean-Jacques hopes out loud that the two would climb the podium together in the Rostelecom Cup.
Jean-Jacques was coached by Celestino at some point in time, but it is not shown whether it was a short training session or long-term coaching .
In the anime, there is barely any interaction between Jean-Jacques and Otabek. However, JJ invited Otabek for dinner while in Barcelona  because he felt sorry that Otabek was alone. Being rink mates in the past, JJ is the one who taught Otabek how to do a quad Salchow .
Short - Theme of King JJ
Jean-Jacques collaborated with a world-famous rock band specifically to produce the music for his short program. The lyrics of this song represent his wish to be above the world and extends this invitation to everyone around him.
Free - Partizan Hope
- "It's JJ Style!"  (JJ's catchphrase)
- "I feel like I have been thrown naked onto the ice for the very first time."  (JJ's GPF free program monologue)
- "I'm the only one in the whole world who can pull of a dream collaboration with a world-famous band!"  (JJ's Rostelecom Cup short program monologue)
- "Let's climb the podium together at the Rostelecom Cup, Yuri-chan!"  (to Yuri Plisetsky)
- The name Jean-Jacques is a French name, which is equivalent to "John James" in English.
- JJ's name was initially Jean Jack, but it was later officially changed to Jean-Jacques.
- JJ's surname Leroy is an old spelling of "le roi", which means "the king" in French.
- JJ's Instagram is Jjleroy!15.
- The caption on his Instagram post reads 'Let's party now! 😎 #Singapore #party #it'sjjstyle'.
- JJ has visited the Raffles Hotel Singapore, as seen on his Instagram feed.
- JJ's practice clothes are from his own original fashion brand, JJ Style.
- JJ does a lot of charity work during the off-season .
- The logo on JJ's red jacket is an inverted version of the logo for Canadian Tire (though the name on it says "Cast Wheels"), a Canadian retail chain which often sponsors athletes.
- JJ is a devout Christian .
- JJ is a top student at Toronto University .
- In Episode 8, JJ crosses his heart while getting in position to begin his short program where it is believed to be part of "The Sign of the Cross" since he is Catholic and this is for a blessing or good luck.
- In Episode 12, JJ appears on the cover of Ice Jewels, a Japanese figure skating magazine.
- According to records, JJ's short program score at the Rostelecom Cup would have eclipsed the current world record by over 2.6 points.
- JJ wears the same coat and hat as Eric Cartman from South Park during his flashback in Episode 12, as a nod to South Park referencing Yuri!!! on Ice in the finale of their 20th season "The End of Serialization as We Know It" .