Lacamoire's early theatrical credits as Music Director, Arranger, and/or Orchestrator include: ; the 2001 National Tour of Godspell; Stephen Schwartz'sCaptain Louie ; and Legally Blonde. He also conducted the cast recording of the 2000 touring cast of Godspell. Lacamoire was also the Music Director of Wicked in 2005, and Music Supervisor for the musical High Fidelity in 2006, as well as assisting with the orchestrations for that show. In 2007, Lacamoire received a Drama Desk Award nomination for Outstanding Orchestrations as Music Director for the Off-Broadway production of Lin-Manuel Miranda's In the Heights. Following its successful Off-Broadway run, In The Heights transferred to the Richard Rodgers Theatre on Broadway. Lacamoire, along with Bill Sherman, won the 2008 Tony Award for Best Orchestrations and the 2009 Grammy Award for Best Musical Theater Album for their combined work on In The Heights. In 2012, Lacamoire and Tom Kitt were the Co-Orchestrators of Bring It On the Musical — another collaboration with Lin-Manuel Miranda — for which Lacamoire also served as Music Supervisor and Arranger. Additionally, Lacamoire wrote the dance arrangements for the 2012 Broadway revival of Annie. in a performance of "The Hamilton Mixtape" at the White House Evening of Poetry, Music, and the Spoken Word in May 2009 Lacamoire was the Music Director, Orchestrator, and Conductor for the Broadway production of Hamilton at the Richard Rodgers Theatre, continuing in the roles he held during the show's Off-Broadway production at The Public Theater, as well as the Co-Arranger of the show's score. In late 2016 Lacamoire transitioned to the role of music supervisor, ending his stint of conducting each show, and instead supervising the music at all of the different productions. Lacamoire won his second Tony Award for Best Orchestrations in 2016 for the Broadway production of Hamilton. The show's Original Broadway Cast Recording was released digitally on September 25, 2015, and by Atlantic Records as a two-disc set on October 25, 2015. It won a Grammy Award for Best Musical Theater Album in 2016, earning Lacamoire his second Grammy as a record producer. Lacamoire is a regular participant in the well-received Ham4Ham performances which have taken place outside the Richard Rodgers Theatre on days when there are both matinee and evening performances of Hamilton Lacamoire is the Music Supervisor of Dear Evan Hansen, a musical for which he won his third Tony award and his third Grammy award. He was the Music Director of Carmen Jones, a 2016 Cuban adaptation of Georges Bizet'sCarmen. For that Cuban-American production, Lacamoire related it entailed channeling music that's “in my blood.” In late 2017, Lacamoire reunited with Lin-Manuel Miranda on his song "Almost Like Praying" to benefit Hurricane Maria relief and recovery operations in Puerto Rico. Lacamoire was the Executive Music Producer on the film The Greatest Showman in late 2017. In March 2018, Lacamoire produced Lin-Manuel Miranda's March 2018 Hamildrop, "Found/Tonight". The song also featured Ben Platt. In April 2018, Lacamoire arranged Miranda's April 2018 Hamildrop, "First Burn". The song featured the 5 Elizas who took on the role after Phillipa Soo left the show in July 2016. Lacamoire is also the orchestrator and co-arranger of Carmen La Cubana, a stage adaptation of Bizet's Carmen that features the classic opera score using all-new Cuban musical arrangements. It began a European tour in July 2018. In July 2018, Alex Lacamoire appeared on The Hamilcast: A Hamilton Podcast for a series of three episodes. The episodes included a musical breakdown of "The Schuyler Sisters" as well as an in-depth discussion of the music from Hamilton. In May 2019, Lacamoire received an honorary Doctor of Music degree from Berklee College of Music.
