All About ONF: Profile, Pre-Debut, Debut Stage, Etc.


Meet the Powerful Boy Group ONF

Lots of K-pop groups make a debut each year, whether it’s a boy group or a girl group. Making the number of groups in the K-pop industry bigger and more varied. But there are always groups who are interesting. They don’t only follow the same concept as the other groups. That’s what makes a group gain recognition and be loved by fans.

And just like that, this boy group that we are going to talk about is also a group that has an interesting concept with their subunits. Let’s check out the sections below to find out more about ONF!

ONF’s Introduction


ONF is a group under WM Entertainment. You must be wondering what ONF stands for? If you guess that it stands for O and F then you’re wrong. Well, not totally wrong, though. But to be precise, the O in ONF means ON, while N is and, and F is for OFF. So, ONF’s group name can be pronounced as ON AND OFF. But you can write it down as ONF to be short.

And why the name is ONF or ON AND OFF, you may ask?


As we told you before, ONF is a group that has two subunits. So, the group has one subunit called ON and the other subunit is called OFF. Since it has two subunits, it also has two leaders. The leader of the ON team is Hyojin, while the leader of the OFF team is J-Us.


The whole group debuted with 7 members who are Hyojin, E.Tion, J-Us, Wyatt, MK, U, and Laun. They released their first single on August 3rd, 2017.

However, Laun departed from the group in 2019. So, there are only six members left. As they have two subunits.

ONF’s Profile


Let’s find out more about ONF in the group profile below!

Group Name: ONF

Debut: 2017

Debut Album: ON/OFF (first mini-album)

Genre: Ballad, rock/metal, dance

Leader: Hyojin (ON team), J-us (OFF team)

Agency: WM Entertainment

Label: Stone Music Entertainment

Fandom Name: Fuse

ONF Members’ Profiles and Facts


Now we have seen what kind of group ONF is. They surely have an interesting concept by having two subunits and two leaders in one group. Seeing their genres too might be making you interested in the group’s songs. Don’t worry, we will be talking more about them.

But first, let’s check out the members’ profiles, which members belong to the ON team and which members belong to the OFF team!

ONF’s Hyojin


Full Name: Kim Hyojin

Stage Name: Hyojin

Birthday: April 22nd, 1994

Birthplace: Seoul, Yaksu-dong, Jung-gu, South Korea

Nationality: Korean

Height: 172.8 cm

Weight: 54 kg

Blood Type: O

Religion: Protestantism

Family: Parents, 1 older sister

Position: ON team leader, main vocal

Interesting Facts:

  • Hyojin’s front teeth are showing when he’s talking or laughing giving him a cute impression.
  • Hyojin participated in MIXNINE, a survival show that aired in 2017. He became the center when they performed a song titled “Just Dance”.
  • Hyojin revealed that he has two tattoos in total. One on the back and the other one is on his wrist.
  • Hyojin is a huge fan of DAY6. He always said it to fans and even mentioned them as the artists that he wanted to collaborate with.

ONF’s E-Tion

wm onf

Full Name: Lee Changyoon

Stage Name: E-Tion

Birthday: December 24th, 1994

Birthplace: Jeollabuk-do, Deokjin-gu, Jeonju, South Korea

Nationality: Korean

Height: 173 cm

Weight: 57 kg

Blood Type: B

Family: Parents, an older brother

Position: Lead vocal

Interesting Facts:

  • E-Tion is full of talents and excitement. He is the type who’s suited to be an entertainer.
  • E-Tion has a lot of tears. Seems like he is the member who likes to cry in an emotional situation.
  • E-Tion has good drawing skills. He designed the T-shirt of ONF which was sold at the ONF official online shopping mall.
  • E-Tion’s hands are very small and cute.
  • E-Tion’s birthday is on Christmas Eve. He said that he’s proud of it and he wanted to listen to Carol songs.

ONF’s J-Us

j us

Full Name: Lee Seung-joon

Stage Name: J-us

Birthday: January 13th, 1995

Birthplace: Seongdong-gu, Seoul, South Korea

Nationality: Korean

Height: 174 cm

Weight: 53 kg

Blood Type: AB

Religion: Catholicism

Family: Parents, two older sisters

Position: OFF team leader, sub-vocalist, lead dancer

Interesting Facts:

  • J-us is the type who can make others feel good because he has a cute tone. Perhaps because he is the youngest in his family.
  • J-us’s MBTI type is ENFP.
  • J-us has been friends with Hyojin for over 14 years.
  • J-us was prepared to be a table tennis athlete when he was in elementary school. But he quit because he was scared of the coach.

ONF’s Wyatt


Full Name: Shim Young-jae

Stage Name: Wyatt

Birthday: January 23rd, 1995

Birthplace: Seongbuk-gu, Seoul, South Korea

Nationality: Korean

Height: 175 cm

Weight: 66 kg

Blood Type: O

Family: Parents, an older brother

Position: Main rapper, lead dancer

Interesting Facts:

  • Wyatt’s English name is Jay.
  • Wyatt went to an international school in Kazakhstan. That’s why he has good English skills.
  • Wyatt’s favorite food is fast food, especially hamburgers.
  • Wyatt tried to get permission from his parents to join an audition for a K-pop agency, but his parents didn’t give him that permission, so he went secretly.



Full Name: Park Min-kyun

Stage Name: MK

Birthday: November 16th, 1995

Birthplace: Gyeonggi-do, South Korea

Nationality: Korean

Height: 178 cm

Weight: 66 kg

Blood Type: AB

Pets: Dog and cat

Family: Parents, older sister

Position: Lead vocal, sub-rapper

Interesting Facts:

  • MK is considered to be the funniest and most hectic member of the team.
  • MK is pretty good at doing a lot of aegyo.
  • On the evening of Monsta X‘s showcase day, MK cried because he thought that if he was better he could make it into the team.
  • MK is not afraid of bugs.


onf u

Full Name: Mizuguchi Yuto

Stage Name: U

Birthday: March 16th, 1999

Birthplace: Osaka Prefecture, Japan

Nationality: Japanese

Height: 170 cm

Weight: 53 kg

Blood Type: AB

Family: Parents, an older brother, a younger brother

Position: Main dancer, sub-vocal

Interesting Facts:

  • U is the first foreign and Japanese idol of WM Entertainment.
  • U started to dance very hard when he was in middle school. He was also the only student who danced in his school back then.
  • U was cast by JYP Entertainment’s staff when he was going home after class. He trained there and met other fellow Japanese trainees such as Yuto from Pentagon and Sana from Twice.
  • U’s Korean proficiency is at a high level.
  • U is friends with UP10TION‘s Xiao and JBJ95’s Kenta.

ONF’s Pre-Debut


As we told you before, ONF made a debut under WM Entertainment. It’s the same agency that oversees B1A4, Oh My Girl, and Lee Chaeyeon from IZ*ONE. You might be wondering how did the agency prepare for their debut day? Well, let’s check out the story of their pre-debut!

onf pre debut

Just like other K-pop idols, before joining the group, ONF members trained to be idols for several years. Some of them trained for over 5 years, some shorter than that. Some members trained in other agencies before joining WM Entertainment. Let’s dig into the members’ trainee lives one by one.


Hyojin was trained for 5 years before he debuted with ONF. Ever since he was a trainee, he always has been a perfectionist. Hyojin always took more time to dance because he wanted to be better. Every day, he practiced for 3 to 6 hours a day. No wonder that he did great in dancing even after he debuted.

onf lee changyoon

As for E-Tion, before he became a member of ONF officially, he was a trainee for 3 years. He got motivated to join the audition in WM Entertainment because of Hyojeong from Oh My Girl. They attended the same dance academy.

j us

While J-us spent 5 years being a trainee before he debuted as a member of ONF. He was known for his real name Lee Seungjoon. He came from Seoul, South Korea. He became a trainee when he was in high school. Unlike other usual idols, J-us attended a general high school instead of a performing arts high school.


Moving on to Wyatt, he came from Seoul too. His real name is Shim Jae-young. He spent the longest trainee period compared to the other members. He has been a trainee in WM Entertainment for 8 years. His mother and Jinyoung from B1A4 know each other. Wyatt too, got support from Jinyoung prior to his debut.

yuto u onf

Unlike Hyojin, E-Tion, J-us, and Wyatt, MK was a former trainee of Starship Entertainment. He trained with Monsta X members. He also appeared in the survival program from Starship Entertainment which aired on Mnet, No.Mercy. However, MK was eliminated from the show. Then he moved to WM Entertainment. MK has been a trainee for 7 years.

U or Mizuguchi Yuto came from Japan. He was born and raised in Osaka. Even when he was still living in Japan, U was interested in dancing and attended a dance academy there. He moved to Seoul after he passed the audition. He trained in JYP Entertainment first before he landed in WM Entertainment. He is friends with some Japanese idols, such as Yuto from Pentagon and Sana from Twice.

onf trainee

All the members of ONF were introduced in WM Dream Tree’s Instagram. The first to be introduced was J-us, or as he was known as SJ standing for his name Lee Seungjoon. He was introduced on May 20th, 2016.

MK’s name and face were revealed next on May 25th, 2016. And the next to be revealed was E-tion as CY which stood for his real name Lee Chang-yoon, on May 30th, 2016. After that, JY or Shim Jae-young, who we now know as Wyatt, was revealed on June 1st, 2016. Next, Hyojin’s turn to be revealed as HJ was on June 3rd, 2016. The last one was U who was revealed on June 7th, 2016, as YT.

All of them have been backup dancers for B1A4 in some of their concerts. They also made cameo appearances in B1A4’s mini-drama.