- Left Heart
Tracklist:
- 사랑할 때마다 – Everytime We Love
- Day ＆ Night (Feat. Baek Ji-Young)
- 왼쪽 가슴 – Left Heart
- 나 나쁘죠 (Feat. Kim Tae-Woo) – Aren’t I Bad
- 하리오 – Will Do
- 사랑은 좋은 거 (Feat. Common Ground) – Love Is Good
- 낡은 사랑 – Worn Love
- 버릇 – Habit
- You (Feat. Sweet Sorrow)
- 천일동안 – For 1000 Days
- Dropping the Tears
Tracklist:
- The Present
- 1초에 한방울 (Feat. Dynamic Duo) – One Drop Per Second
- 눈물이 뚝뚝 – Dropping the Tears
- 소녀, 사랑을 만나다 (Feat. Girls’ Generation Tiffany) – Girl, Meets Love
- 쇼핑 – Shopping
- Love 119 (Feat. MC Mong)
- 눈물이 뚝뚝 (Inst.) – Dropping the Tears (Inst.)
- 소녀, 사랑을 만나다 (Inst.) – Girl, Meets Love (Inst.)
- Miss, Miss and Miss
Tracklist:
- 바람 – Wind
- 그립고 그립고 그립다 – Miss, Miss and Miss
- 반복일 뿐이야 – Just a Repeat
- 최면 (Feat. Outsider) – Hypnosis
- 눈물연못 – Pond of Tears
- 사랑해 반대말 – Antonym of I Love You
- 끊었던 담배 – Once Quit Smoking
- 필름이 끊겼다 – The Film Stopped
- 이별 몰랐던 날 – The Day I Didn’t Know Farewell
- 초콜릿 (Project: Color Chocolate) – Chocolate
- My Last Love
- 사랑 후유증 – The After effects of Love
- 다시 사랑하면 안되니 – Can’t We Love Once Again?
- 사랑한단 말을 못해서 (소울 스페셜 OST) – They Can’t Love (Soul Special OST)
- 나무 – Tree
- 소원 (대왕세종 OST) – Wish (The Great King Sejong OST)
- 내 가슴이 운다 – My Heart Cries
- 그립고 그립고 그립다 (Inst.) – Miss, Miss and Miss (Inst.)
- My Heart is Beating
Tracklist:
- 분다 – Blow
- 입이 떨어지지 않아서 – Speechless
- 가슴이 뛴다 – ㅡMy Heart beating
- 증상 – Symptoms
- 기가 차 (Feat. Supreme Team & Sistar) – Amazed
- 선물 (Feat. Eun Ji Won) – Present
- 입이 떨어지지 않아서 – Speechless (Inst.)
- 가슴이 뛴다 (Inst.) – My Heart beating (Inst.)
- I Need You
Tracklist:
- 부른다 – Calling You
- 니가 필요해 – I Need You
- 내가 싫다 – I Hate Myself
- 못된 생각 – Nothing Left
- Will이라고 해 – I’m Will
- 네 곁에 – I’ll Be With You
- 니가 필요해 (Inst.) – I Need You (Inst.)
- The 3rd Album Part.1
Tracklist:
- Closing My Eyes (Intro)
- Butterfly
- Please Don’t…
- Come To My Crib (feat. Beenzino)
- Hey You (feat. Choizaof Dynamic Duo)
- You’re So Beautiful
- Bluffing
- The 3rd Album Part.2 ‘Love Blossom’
Tracklist:
- 봄날의 기억 (Spring Memories)
- Love Blossom
- Bon Voyage (Feat. Beenzino)
- Lay Back
- 추억이 울려 (Memories Ringing)
- Marry Me
- 신호등 앞에서 (Fade Out)
- Will In Fall
Tracklist:
- Fall In Fall
- 촌스럽게 왜 이래 (You Don`t Know Love)
- 니가 아닌 것 같아 (It’s Not You)
- 첫 사랑은 죽었다 (First Love end)
- Bubble (Narr. Bora ofSistar)
- 말실수 (A Slip Of The Rongue)
- One Fine Day
Tracklist:
- So Pretty
- Day 1
- Sweet Girl (Feat. LE of EXID)
- A Bright Day
- Love Love Love
- Last Digit
COLLABORATIONS:
-Lim Jeong Hee – 운명 – Destiny (2006)
-Uhm Jung Hwa – Come 2 Me (2006)
-Epik High – Music (2007)
-8Eight – 들어요 Listen (feat. Lim JeongHee&K.Will) (2007)
-Hye Mi – You’re My Everything (2007)
-Suho – 그냥 이렇게.. Just Like This.. (2007)
-MBC Music Travel LaLaLa Live Vol.5 – Nan Sarangeul Ajik Molla // Over the Rainbow (Moony &K.Will)) (2009)
-Project: Color Chocolate – 초콜릿 Chocolate (K.Will, Mario) (2009)
-Mighty Mouth – WHY (2009)
-Taw – 내 여자 친구를 소개합니다 I Introduce My Girl friend (Feat. Bae Soo-Youn, K.Will) (2009)
-E Sung – 여.친.소 Yeo Chin So (With Taw, Kim Hyung Jung) (Feat. K.Will) (2010)
-Blue Brand – 아무 말도 하지마 Don’t Say Anything (JP Kim Feat. K.Will) (2010)
-Navi – 우리 정말 사랑했어요 We Really Loved Each Other (2010)
-Gilme – 미안해 사랑해서 Sorry, I Loved You (2010)
-Zia – 사랑을 가르쳐 주세요 Please, Show Me Your Love (2010)
-The Name – 겨우 살아 Barely Alive (2011)
-Zia – 그대이길 바래요 Hope It is You (2011)
-Sistar ,Boy Friend – Pink Romance (2011)
-Starship Planet 2012 – White Love (2012)
-Mamamoo – Pappermint Chocolate (2014)
Kpop Weekly 