"Tank Dempsey: American hero. Hand him a loaded weapon, a good woman, and something to shoot at and he is happy. Enrage him and he will rip your guts out and use them as a bandolier.
Dempsey was selected for this mission after he showed his true grit at the battle for Peleliu. Remarkable though it may seem, his unit was captured during the early raids before the main invasion, and he spent 2 weeks in a rat infested bamboo cage submerged in malarial water. Well that did not stop The Tank. After he gnawed his way through the cage, he then gnawed his way through his captors armed only with a Bobby pin and his Medal of Honor which he keeps secreted in various body cavities.
Now you know there is no before the war for Dempsey, and there is no after. There is only the legend of Tank Dempsey, and how he will win the war for the rest of us."
"November 19, 1917 It seems beyond doubt that Fritz is up to no good. Air reconnaissance suggests prototype armored weaponry is being tested in Northern France. Scuttlebutt reads like the ramblings of a mad man; strange lights in the sky... a mysterious plague... even giant metal men. I'll be at the site within the week to learn the truth with my own eyes..."
— Tank Dempsey
"April 14, 1918 After far too long waiting on the sidelines, we finally got our first taste of combat. Our actions at Belleau Wood seem to have brought their Spring Offensive to a grinding halt. We even heard talk that Fritz has nicknamed us the 'Devil Dogs', following the allround ass kicking they took... and that's fine by me. We intercepted communications suggesting that we're not the only nation to learn of the enemy's plans. Scuttlebutt is that the Russians & Japanese are looking to grab a slice of the action. Things are going to get interesting. DEMPSEY"
In a file on the computer terminal, it says that part of Dr. Maxis' super-soldier experiments were Dempsey, Nikolai, and Takeo.
When Pack-a-Punching a weapon on Ascension, he may say, "Richtofen... I don't like him. I think I saw him before Shi No Numa but... I can't quite remember. In fact, I can't remember much at all before then." Likely referring to Richtofen having his memory wiped.
Along with Takeo Masaki, Nikolai Belinski and Edward Richtofen, he is found in Call of the Dead involved in the Original Characters Trapped Easter Egg.
In Call of Duty: World at War, the player who is Dempsey will always be the host of the game, while in Call of Duty: Black Ops, it is randomized. Additionally, if the player is playing on Shi No Numa or Der Riese solo in Call of Duty: World at War, they will always be Dempsey.