Composer, Orchestrator, and Pianist, Mariko Horikawa was born in Tokyo, Japan. Influenced by her parents, Mariko started playing the piano at the age of two. Mariko's career as a pianist, she won a first prize in the State Competition in the U.S. at the age of nine. After she came back from the U.S., she auditioned for Japan Piano Teachers Association(JPTA) and became a member. She entered Keio University and started playing in the band as a keyboard player and played R&B, Soul Music, J-pop, Acid Jazz, and Fusion Music. This experience influenced her future piano life. After graduating from Keio University, she worked for Yamaha Corporation. She never forgets her desire toward music and enrolled in Berklee College of Music. She graduated from Berklee with a Bachelor of Music (majoring in Film Scoring). While attending Berklee, she had selected to several awards such as Berklee Contemporary Piano Performance Award and so on. Mariko had joined several recording sessions and clinics for Berklee's promotions. Mariko also joined Berklee Contemporary Symphony Orchestra as a Pianist and performed with conductor, Francisco Noya, Richard Sebring(French Horn Player), and George S. Clinton(Composer). Mariko also performed at Boston Symphony Hall as a pianist and a celeste for Final Fantasy Tour in Boston, lead by arranger, Arnie Roth.

Encouraged by her teacher, she started writing music at this time. Mariko's compositions and arrangements had been selected and awarded couple times.

After graduating from Berklee, Mariko moved to Los Angeles and started her career as Composer, Arranger, Orchestrator, and Pianist. Mariko joined several Blockbuster Movies and TV shows in Hollywood, such as La La Land, Star Wars the Last Jedi, Namiya, and so on. Mariko was also nominated and received several awards, such as International Film Festival in Milan and Sound Creators of the Year in Japan and so on, and performed in several theaters in Boston, such as, The Platform Playwrites' Festival in Boston, MA.

​

Mariko is now working as freelance composer, arranger,orchestrator, and pianist, both in Japan and in the United States.