Their first public ticketed concert occurred on December 11, 2015, at the Montalban Theater in Hollywood, featuring Vivaldi's Four Seasons, performed by Los Angeles Philharmonic concertmaster Martin Chalifour.
Other soloists appearing since this inaugural concert have included violinist Sarah Chang, pianist Molly Morkoski, clarinetist Eddie Daniels, and singers Úyanga Bold, Cindy O'Connor, Tyler Duncan, Eleni Matos, Garth Neustadter, Franchesca Retford, and Holly Sedillos.
[3][4][5] On July 24, 2016, the HCO commissioned and premiered seven new works by composers Michael Barry, Chad Cannon, Andy Forsberg, John Kaefer, Brian Langsbard, Susie Benchasil Seiter, and Andrew Morgan Smith.
[15][16] On November 11–13, 2016, the HCO was the featured orchestra for the Orange County premiere of Harry Potter and the Sorcerer's Stone, live-to-picture, conducted by Justin Freer and produced by CineConcerts, at the Segerstrom Center for the Arts in Costa Mesa, CA.
On December 17, 2016, the HCO accompanied Andrew Lippa in the world premiere performance of Swan Lake: A New Musical in Concert, composed by Peter Seibert and J. Patrick Lundquist, at the Montalban Theater in Hollywood.
[26][27] On June 16, 2017, at Colburn School's Zipper Hall, the HCO presented violinist Nathan Cole, the first associate concertmaster of the Los Angeles Philharmonic, in a traditional program of Bach, Grieg, and Copland.
The 2018 edition featured the composers Germaine Franco, Tamar-kali, Ronit Kirchman, Cindy O’Connor, Heather McIntosh, Mandy Hoffman, Tori Letzler, Emily Rice, Perrine Virgile-Piekarski, ASKA, Tangelene Bolton, and Jessie Weiss.
[32] On March 30, 2019, the HCO was the featured orchestra for the west coast premiere of the live-to-film concert version of the 1993 film Rudy, with music by Jerry Goldsmith; conducted by Justin Freer, and produced by CineConcerts.
[36] On April 26, 2024, the HCO was the featured orchestra for the LA premiere of "Outer Wilds:Live with Andrew Prahlow" at the Montalban Theatre in Los Angeles, with Mark Robertson, conductor.
[43] He also served as concertmaster for the recent and upcoming films One Night in Miami, White Men Can't Jump, Rather, Big City Greens: Spacecation, The Boogeyman, Strays, The Hunt, Shaft, The Biggest Little Farm, The House with A Clock in Its Walls, Triple Frontier, The Nun, and Under the Silver Lake, in addition to previous films including Baywatch, Pitch Perfect 3, Contagion, Much Ado About Nothing, Ride Along 1 and 2, Premium Rush, Blackfish, Merchants of Doubt, and Horrible Bosses 1 and 2.
[44] On the pop music side of things, Mark has worked with Logic, A Great Big World & Christina Aguilera, Billy Childs, Daughtry, OneRepublic, the Fray, and Kelly Clarkson, among others.