[9] In 2000, Tin moved to Los Angeles and continued to arrange scores for Silva Screen Records while searching for more permanent employment.

[15] In response, Tin composed "Baba Yetu" for the main theme, a choral, Swahili version of the Lord's Prayer recorded by his former a cappella group, Stanford Talisman.

It is a popular competition piece, as in 2014 the Welsh choir Côr CF1 won BBC Radio 3's Choir of the Year with their performance,[33] and in 2018 two separate contestants competed with "Baba Yetu" on the same season of America's Got Talent, being the Angel City Chorale, who were awarded the Golden Buzzer by Olivia Munn,[34] and Zurcaroh, who reached the finals with an acrobatic dance performance to the song.

[40] It also entered Tin into the Guinness Book of World Records as the composer of the first video game theme to win a Grammy Award.

[44] It features performances by the Royal Philharmonic Orchestra (conducted by Lucas Richman), Soweto Gospel Choir, Lia, Aoi Tada, Kaori Omura (大村香織), Jia Ruhan, Dulce Pontes, Anonymous 4, Frederica von Stade, Sussan Deyhim, Stanford Talisman, and On Ensemble.

[20] On July 19, 2016, the Royal Philharmonic Orchestra performed excerpts with the combined Angel City Chorale, Prima Vocal Ensemble and Lucis choirs at Cadogan Hall in London.

[26] On July 5, 2017, at the 70th Anniversary of the Llangollen International Musical Eisteddfod, Tin himself conducted the entire work with the Welsh National Opera Orchestra and a group of international soloists, including Elin Manahan Thomas, Nathalie Pires, Joel Virgel, and Nominjin, and a mass choir made up of singers from Wales, South Africa, Taiwan, and the United States.

[47] It consists of ten songs, each sung in a different language, beginning with Proto-Indo-European and including Bulgarian, Turkish, Mongolian, Xhosa, Ancient Greek and Sanskrit.

The album was recorded at Abbey Road Studios with Tin conducting the Royal Philharmonic Orchestra, and features guest performances by the Soweto Gospel Choir, Le Mystère des Voix Bulgares, Kardeş Türküler, Dulce Pontes, Nominjin, Roopa Mahadevan, Anonymous 4, the Angel City Chorale, and Norwegian chamber choir Schola Cantorum.

"[51] The piece was given its world premiere in concert on July 19, 2016, at London's Cadogan Hall, conducted by Tin and performed by the Royal Philharmonic Orchestra, Angel City Chorale, Lucis and Prima Vocal Ensemble combined choirs.

[53] The album, like The Drop That Contained the Sea, was recorded at Abbey Road Studios, with Tin conducting the Royal Philharmonic Orchestra, and features guest performances by Danielle de Niese, Pene Pati, ModernMedieval Voices, Anna Lapwood, the Pembroke College Girls' Choir, the Royal Opera Chorus, and The Assembly.

[57] The album is a musical memorial to bird species driven to extinction by humankind and a celebration of their beauty, while also presenting a warning about humanity's own tenuous existence on the planet.

[58] It consists of twelve movements, ten of which use texts by poets Emily Dickinson, Sara Teasdale, Edna St. Vincent Millay, and Cristina Rossetti, along with two purely instrumental tracks.

[59] The Lost Birds was premiered virtually by VOCES8 as part of their 'LIVE from London' series on October 15, 2022, featuring The VOCES8 Foundation Choir and Orchestra, with Barnaby Smith conducting.

[61] The work’s live premiere occurred on February 25, 2023, at Stanford University, with Tin conducting VOCES8 and the VOCES8 Foundation Scholars, and featuring a reduced chamber orchestration performed by the Friction Quartet and pianist Keisuke Nakagoshi.

Confused as to why her son was listening to classical music, she discovered that he had in fact been playing Civilization VI, which features Tin's piece "Sogno di Volare".

Zambello paired Tin up with playwright Susan Soon He Stanton, who wrote a new libretto to replace the ending written by Giuseppe Adami and Renato Simoni.

[65] The reviews were very positive:[66] Michael Andor Brodeur of The Washington Post called the production 'refreshing' and declared "Even without the new ending — and Tin's splendid musical additions, which draw sensibly from Puccini's score while applying an entirely new emotional finish — Zambello's "Turandot" crackles with fresh energy".

It featured a variety of Renaissance and Romantic era poems (from Thomas Carew, Christina Rossetti, and John Donne, among others) reinvented as lyrics for trip hop and synth pop songs.

[74] Tin arranged a number of jazz tunes for 2018 film Crazy Rich Asians, with one being based on the Chinese melody "When Will You Return?".

[75] Tin's other film credits include writing additional music for Sausage Party (2016), Suddenly Seventeen (2016), Tess (2016), Dante's Inferno: An Animated Epic (2010), Dead Space: Aftermath (2011), Hoodwinked Too!

[76] Tin was a judge on the 2017 season of the Welsh TV show Côr Cymru, a singing competition for amateur choirs airing on Welsh-language channel S4C.