Though an Arizonian by birth, Guillermo grew up as the oldest of six children in Monterrey, Mexico. In 2018, he received his Bachelor of Arts in Classics from Trinity College Dublin. It was during his last year in Ireland that Mr. Dillon discovered and fell in love with the optima via (best way) to learn and teach Latin, that is, by speaking it! After college, Guillermo returned to Monterrey where he enjoyed being an elementary school teacher in an all-boys school for a year. He then pursued an M.A. in Classics at the University of Kentucky, specializing in spoken Latin, where he also worked as a Latin teacher at a classical school in Lexington. In the summer of 2021, he returned to Monterrey and worked as an English teacher, now in middle school, for another year.

During his two years of teaching in Mexico, Guillermo discovered that he also had a hidden passion for children’s literature. This passion then led him to start a literature academy in his own house, where he and his wife would hold several book clubs for children and teenagers during the evenings after school.

Guillermo and his wife, Mariana, have two kids (the third one on the way!) and live in the Chicago suburbs. Apart from reading and speaking Latin and Greek, his hobbies include doing nature walks, reading good books, playing basketball and soccer, and spending time with family and friends.