MCND’s Castle J: Profile, Age, Real Name, Etc.

castle j

A Prince Who Came From a Castle? He’s MCND’s Castle J

A prince who came from a castle? You are probably wondering how is that possible. Oh, we kid you not, this idol that we’re going to talk about not only came from a castle, but he’s a castle himself.

He’s Castle J from the boy group called MCND! You probably have heard about MCND before. Or have you? Well, if you haven’t, it’s time to learn more about MCND and one of their members, Castle J. So, stay tuned to get more info about the amazing leader of MCND, Castle J!

MCND’s Castle J’s Profile

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Full name: Son Seong-joon/Son Sung-joon

Korean Stage Name: 캐슬제이

Korean Real Name: 손성준

Stage Name: Castle J

Nickname: Goryong, Baby Fox

Birthplace: Anyang, South Korea

Nationality: Korean

Height: 176~177 cm

Foot size: 265 ~ 270 mm

Birthday: May 31st, 1999

Zodiac Sign: Gemini

Chinese Zodiac: Rabbit


Position: Leader, main rapper

Occupation: Singer, idol

Blood type: A

Family: Parents

Debut as an actor: 2009

Debut in MCND: 2020

Agency: Top Media

MCND’s Castle J’s Facts

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  • Before debuting as an idol, Castle J was known as Son Seong-joon or Son Sung-joon as a child actor.
  • Castle J learned taekwondo and was in the level 3-dan.
  • Castle J admitted that he has a lot of fears and a lot of tears as well.
  • Castle J is friends with WekiMeki’s Yoojung for around 10 years, Yoojung revealed it herself on her Instagram.
  • Castle J hates snakes, bees, and also exercise.
  • Castle J is interested in accessories, so he plans to pierce his ears someday.
  • Castle J’s favorite thing is music and games.
  • Castle J has more aegyo than he thought he has.
  • Castle J has two puppies in his family’s house.
  • Castle J’s favorite color is purple.
  • Castle J’s favorite ice cream flavors are “shooting star” and “pistachio almond”.
  • Castle J joined a competition called Feedback Competition Youth in 2017 and won second place.
  • Castle J won the Las Vegas Crowd Favorite title in World of Dance Season 1 in 2017.
  • When he was a trainee, Castle J was a part of a dance group called Top Bro jr.
  • Not only he can rap, but Castle J can also write lyrics.

MCND’s Castle J’s Pre-Debut

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We have gotten to know Castle J better by seeing his profile and the list of interesting facts about him. You probably started to like him even more after getting closer to him. But some of you probably are curious about how Castle J ended up being an idol, especially in Top Media, debuting as the leader of MCND.

So, wait no more, let’s see the full story of Castle J before he made it into what he is right now!

Castle J, as you may already know from his profile, is not his real name. Instead, Castle J was born with the name Son Sung-joon. He was born on May 31st, 1999. Castle J lived in Anyang along with his parents, he is an only child. Making the members of MCND like his own brothers since he doesn’t have any siblings.

Castle J has been dreaming of becoming a superstar. However, being an idol was probably not a path that Castle J was thinking he would choose back then. Instead, he was focusing more on being an actor.

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At the age of 11 in the Korean age system, or more precisely in 2009, Castle J who was known by his birth name Son Sung-joon, began his career as a child actor by starring in a drama. Not only that, Son Sung-joon who was a cute little boy back then also starred in some commercials.

Son Sung-joon then spent the years of his childhood life starring in some dramas or even TV movies even though he was just a supporting role back then. He played in a drama that starred Kim Hee-ae, Choi Ji-woo, and many more.

In 2015, instead of joining an agency that focused on the acting field, Son Sung-joon or Castle J then started to be a trainee in Top Media, the agency that he is in right now. Son Sung-joon or Castle J joined the agency around the same time as the trainees that we know as MCND members: Minjae and Huijun.

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In 2016, the three of them, Son Sung-joon or Castle J, Minjae, and Huijun learned more about dancing in America. Not only that but BIC, another member of MCND also joined them in the journey of a dancing lesson in America. Just like Jungkook from BTS, before he debuted with BTS, Jungkook also went to America to learn dancing. No wonder Castle J, BIC, Huijun, and Minjae are good at dancing now.

After that, Castle J, Minjae, Huijin, and BIC came back to Korea. But they didn’t make a debut just yet at that time. As you may know, Castle J was still young back then. Also, there could be a lot of things that Castle J should learn to make him a better performer.

MCND’s Castle J’s Debut


We have seen how Castle J spent years being a trainee in his pre-debut era. You may have known too that Castle J was a child actor back then. He could be continuing his career in acting and probably become a rising actor such as Nam Da-reum, Yeo Jin-goo, Park Ji-bin, etc. But Castle J chose the path to be an idol after he decided to be a trainee in Top Media.

But still, he had to wait for years after becoming a trainee and even spend time in America to get better at dancing. Castle J still had to wait for years and watch his friends debut in other companies while waiting. But fortunately, the patience of Castle J and the other members came to an end.

In early 2020, Top Media revealed that they were going to debut a new boy group. Top Media’s new boy group is called MCND which stands for “Music Creates New Dream”. Just like the meaning behind their name, hopefully, MCND can help their fans dream just by listening to their music.

And the long-awaited debut day finally arrived on February 27th, 2020, where the boy group called MCND released a debut song titled “ICE AGE”. Let’s see the music video of “ICE AGE” down below!

What do you think of the “ICE AGE” music video by MCND? The song’s title is the same as the movie Ice Age. But the lyrics of this song tell about the era of the ice age that is so cold and frozen. The lyrics are written by Castle J himself! All members of MCND also sing really well and perform amazing raps too.

And now, let’s see the dance performance of MCND on their dance practice!

Woah, the theme of their dance practice is Frozen. All five members wear costumes of Frozen such as Elsa, Anna, Olaf, Kristoff, and Sven. Should they do a cosplay of the Ice Age movie too? Let us know your opinion in the comment section!