In the show, Poseidon will be played by Black Sails actor Toby Stephens and is described in the Lightning Thief book as "tall, handsome, powerful, yet gentle" with dark hair, a beard, and a Tommy Bahamas button-up.

Although many of the main cast has already been set, including Walker Scobell as Percy, Leah Sava Jeffries as Athena's daughter Annabeth, and Aryan Simhadri as the satyr Grover, the casting for Poseidon and Zeus have been kept under wraps despite Riordan teasing that the series has been filming with them for some time.Today, the official Percy Jackson account has finally revealed that Percy Jackson's father Poseidon will be played by Toby Stephens and Zeus will be played by Lance Reddick.

The actor who plays  Percy Jackson’s father, Poseidon, in Season 1 isToby Stephens.

Toby Stephens plays Poseidon, the god of the sea and Percy's father. Toby Stephens plays Poseidon.