He returned to Spain with his family when he was a teenager and worked as a model and started taking acting lessons before going on to appear in Spanish stage, TV, and film productions.
The actor was best known for his roles on daytime soaps. After first appearing on Days of Our Lives in a one-off role in 2010, San Martin was cast as Dario Hernandez on the daytime soap. He appeared in the roll for more than 50 episodes over a six-month period in 2011, per his IMDb profile. The character ultimately returned to the show in 2016, but was portrayed by Guiding Light alum Jordi Vilasuso.
San Martin followed his role in Days with a part in the 2013 TV movie Behind the Candelabra before he returned to daytime television in 2017 for an arc
