Via Instrumental Casting, Jay performed with an orchestra to a sold out crowd at the Dolby Theater in Hollywood with Persian Artist Shahkar and guest artist Andrea Bocelli. Via Instrumental Casting, Jay also appears as a violinist in an iPhoneX commercial, on the FX TV show called Better Things, in music videos for Hilary Roberts 'Fight to the Other Side' and Aloe Blacc;s 'Love is the Answer' which is also featured in a Lincoln car commercial, and in an episode TV's Nip Tuck. He has also played numerous live engagements and done recording work via Instrumental Casting.
At the age of 9, Mr. Hallmark was invited by Lord Yehudi Menuhin to study at the Menuhin School in England, where he participated in over ninety performances and tours scheduled per year. At the age of 14, Mr. Hallmark won first place in the British Young Artists Competition. Since graduating from Julliard in 1994, with his Masters of Music Degree, Mr. Hallmark has been much sought after as a chamber musician and chamber orchestra player. He is a co-founder of the Concertante Chamber Players based in New York, performs regularly with the ProArte Chamber Music Consortium in Guanajuato, Mexico, and has been concertmaster of the Aspen Valley Chamber Orchestra, in Colorado, for 11 years.