David Martinez was a night school Spanish teacher who teaches the class Will took in The Spanish Teacher, the twelfth episode of Season Three.
He is described as "the hottest Spanish teacher in Ohio history." He was offered a Spanish teaching position at McKinley to replace Will, who decided that he was not good enough to teach Spanish, and only fit for the Glee Club.
He is portrayed by actor and singer, Ricky Martin.
David comes in as a Spanish tutor who teaches night classes, which Will takes to improve his Spanish. His impressive Spanish techniques and charisma catches the eye of Will who invites him to a cup of coffee, which he accepts. After speaking to Will he reveals he used to be a tooth model and that he enjoys singing and wishes he could set up a night school glee club.
He reveals that he is from Ohio, despite his impressive Spanish, but has grown up from Chilean parents who grew up speaking Spanish. His main intention is to teach kids rather than his old job working as a tooth model. He is then invited by Will to the Glee Club to "spice up" the Spanish assignment for the week. He, along with the New Directions, performs a partly Spanish rendition of Sexy and I Know It.
David later performs La Isla Bonita with Santana to enhance the Spanish feel, which, at the same time, intimidates Will. At the end of the episode, will admits his mediocrity in teaching Spanish, revealing he is stepping down from the job. When Will offers it to him, he is overjoyed and hugs Will in gratitude.
He is briefly mentioned by April after Holly says there is a Facebook group for people who have been guests of the Glee Club. According to April, he is part of this group.