Sammy Valdez was the boyfriend/friend of Hazel Levesque's during her childhood. He is Leo Valdez's great grandfather, and also went to St. Agnes Academy for Colored Children and Indians during his childhood before moving to Houston, Texas.
Sammy Valdez lived in New Orleans during the same time as Hazel back in the 1940's. Because Hazel's mother was using cursed stones, kids and adults would bully her. Sammy was Hazel's only friend during this time. He also took care of the horses owned by more fortunate families and would sneak Hazel into the stables on occasion to help and let her ride. For her birthday, he took her horseback riding and they set up a picnic where he gave her a cupcake. Unfortunately, Hazel's mother was convinced to move to Alaska by Gaea, and Sammy never saw Hazel again and may not even know where she went at all. Sammy moved to Texas and started a family, although he never forgot about Hazel. He died in the 1960's from a heart attack, or so Gaea claims.Camp Jupiter, Hazel mistakes him for Sammy as the two look almost identical and Percy remembers how Leo looked a lot like Sammy from the photograph, but tells Hazel that can't be him as he would be over 70. According to Gaea, he moved to Texas and married at some point, but later died of a heart attack in the 1960s, having never forgotten about Hazel.
Hazel and Leo also share a blackout together, where it shows Sammy rocking a little baby in Texas. The baby later turns out to be Leo, Sammy's grandchild.
- Leo Valdez looks completely identical to Sammy. It has been revealed that Sammy is Leo's great-grandfather.
- Leo was born in Texas, and that is where Sammy moved to as an adult.
- Sammy Valdez was born in the 1940s, which is when the average grandfather of a teen was born.