David Rennington was the owner of Rennington Steel when it faced a financial crisis. He embarked on a life of crime to save his company, but he was promptly stopped by Batman and was subsequently arrested.
Later, he was recruited for the League of Assassins by Ra's Al Ghul.
- Throwing: Skilled with knives.
- This version of Dagger, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 2 Appearances of David Rennington (Earth-One)
- 2 Images featuring David Rennington (Earth-One)
- Quotations by or about David Rennington (Earth-One)
- Character Gallery: David Rennington (Earth-One)