Prior to his time at Imageworks, Sarmiento was a lead facial animation artist at Digital Domain. There, he developed facial deformation techniques that were used on I, Robot's Sonny character, which garnered an Academy Award nomination for Best Visual Effects.

Sarmiento began his career at NBC's Enteraktion Studios in Florida. He is skilled in the use of Autodesk Maya and has been a featured speaker at the Maya 3December events. He also authored the Maya Training Series 1 DVD set for Total Training.