In 2005, Tatum ran into Funimation ADR director Christopher Bevins, who cast him as Rikichi in Samurai 7.

Tatum has been cast in several notable roles, including Kyoya Ootori in Ouran High School Host Club, Sebastian Michaelis in Black Butler, Tomoe in Kamisama Kiss, France in Hetalia: Axis Powers, Erwin Smith in Attack on Titan, Okabe Rintaro in Steins;Gate, Eneru in One Piece, Tenya Iida in My Hero Academia and Rei Ryuugazaki in Free!

Since October 2018, he and Jamie Marchi co-host the ghost story podcast Ghoul Intentions.

[3] During a panel at Ichibancon 2014, he had said that he came out to his family during his college years, with his father having already known about his sexuality for some time.

On October 16, 2018, he became engaged to his long-time partner and fellow voice actor Brandon McInnis in Paris.