All of the current The Boss' members were part of Xing but not always.

In the original squad of Xing  which formed in 2006 were not The Boss' members yet. In 2006 - it included 4 original members of Xing : Kevin Woo (Who is now in U-Kiss) , Marumir ( Kim Ki Bum who was a part of U-Kiss but since 2011 is not a member anymore) , Yume (Kim YoungKyung) and Cheon Hyesung( Choi SungSoo). Later joined two trainees : Poppin dragon ( Yon Junhyung who is a part of U-kiss now) and ZEN 

On August 5 2007 KiBum left Xing and Xing became 5 members group (Kevin, Yume,Cheon Hyesung, JunHyung and Zen). On December 2007 Xing  faced another change : Sungsoo left the group with no further words from him or the Xing Entertainment. Sungsoo was replaced by Hyunmin (known as 'Husky' for his deep voice)  On 12 January 2008 Youngkyung also left the group. On January 13 2008 the group was left also by Junhyung. From now on  the group remained  with Kevin, and Jinhyun along with  members of 'Singing in the rain ' : Jisang, , Lee SuHoon (White) and Shin Gwangchul (Gun). Then joined new dancer Jeon Jihwan (Jay-Kiparang). From then the group consisted of 7 members. 

April 2 2009 was the day when the only one former member of  Xing , Kevin, decided to leave. It was a statement then that 'Xing is a come and out rotating group and that shall help refresh the group. After the only one left, Jinhyun ,two new members were added: Lee injun( Soul) and Park Hyun Cheol ( Rising). 

Xing's songs where The Boss members sang featuring other : 

The first Noel  (Hyunmin feat Kevin ),  Haru Haru (Day by Day, originally by Singing in the rain) , I am really fine(jeongmal Gwaenchanha-yo by Hyunchul, Suhoon, Hyunmin, Injoon , ), Memorize, Hi-five, Sarang (Love by SuHoon , Hyunmin, Jisang)

The ones in Xing who consisted of:Kim Wanchul, Kim donggeun, Jin HyunJin, Hwang Doohwan, and Kim Jinwan started with the teaser for new mv, but it was never realesed. Eventually , Xing disbanded, and the company felt having pulled lawsuit by threatening the singers and being treatened unfair .

In the end, Mika, Hyunmin, Karam, InJun and jay  formed new group under  Open World Entertainment. Originally The Boss was meant to be  7 members with Gwangchul and Jisang , but the both of them decided not to join for personal reason:one had personal reason, whiel the other did not want to be a part of the group anymore

       The Boss released their first single on 4th March 2010 called : Admiring Boy /Dongyongsonyon and it includes two singles :

1.Amring Boy/The admirer  (also known as Tokyo Boy, Admirable boy)

2. Shining World

Shortly after the single their release their first mini-album called 'Awake' it includes :

1. Intro (the boss /Wobler/ )

2.  Stumble Stumble (Biteul Biteul) 비틀비틀

3.  Nobody Anybody... (also known as No one, Any one  , Amudo Nugudo) 아무도.. 그 누구도

4. New Boyz

5. The One

6.Shining world (눈부신 세계)

7. Admiring Boy (동경소년 ) 

On January 2011 forms sub-unit called Popsicle which consists of Mika , Karam and Jay. They release the mv called 'I'll love you untill it snows in the middle of the summer day" The promotion ended on 22nd January 2011. On 20 january The Boss WON an Award - the Newcomer Award at 20th Seoul Music Awards. On 23rd January they   flew to Japan to start the activity. On February 2011  on their official site was stated that the official color of DGNA is Pearl Terracotta.

On 20 March 2011 the Boss released their first Japanese single from 'Love' series. First i nthe queue was ' Love Power' . since September 2010 in 6 months they studied Japanese and they already mastered it to the point so the communication was not the problem anymore.

Single Love Power consists of  songs :

1. Love Power

 2.奪いたい今すぐに (I want to snatch youl  away right now) (Ubaitai, ima sugu ni)

3. もう最後になると (It Will Be the Last) (Mou saigo ni naru to) 

4. まだ見ぬその未来へ (To the Unseen Future) (mada minu sono saki e)

5. Love Power -instrumental-

   On June 15th 2011 The Boss released second of 'love' series single called 'Love Bingo' 

Love Bingo single consists of : 

1.Love Bingo! 

2.MAGIC

3. 夏の記憶 (Summer's Memories) 

4.Love Bingo! -instrumental-

On 21 September 2011 The Boss released their third and last from 'Love' series single, Love Parade 

It consists: 

1. Love Parade

2. Girlfriend (OST, Guruguru Ninety Nine (Nippon TV) 

3. わすれない (Wasurenai/Don't Forget) 

4. Love Parade -instrumental-

  After  almost one year  in Japan, The Boss came back to Korea it seemed they have been forgotten. On September  came out beautiful single called' lady' . It was released on 26 October 2011 . Lady consists of : 

1. Lady

2. Calling you

3. Lady -instrumental- 

   Only  one month in Korea and the Boss had to comeback to Japan.On 7 December came  another Japanese single called 'Love Days' and it consists of the songs:

1. Love Days

2. taiyou Ga Noboru Basho ( 太陽が昇る場所 -The Place where the sun rises)

3. Futari no suki na akane sora  ( 二人の好きな茜空 - Our Favorite Sunset Sky)

4. Love Days (Beat & Instrumental ver.)

    On January 18 2012 The Boss released their first Japanese album, Love Letters.

Love Letters consist of : 

1. Love Power

2. Love Story

3. Love Days

4. Love parade

5. Friends 

6. Kataomoi ( 片想い)

7. Mou saigo ni naru to ( もう最後になると )

8. Love song for you.

9. Love