Born to the life and leisure of British aristocracy, Cosmo rose to prominence as a gentlemen detective. An accomplished thespian and master of disguise, he traveled the world, unraveling several seemingly inexplicable mysteries during the 1930s.
In his first recorded adventure, Cosmo matched wits with an enemy agent named Taro, who was every bit the sleuth and master of disguise that Cosmo was. Shortly thereafter, he traveled to Capetown, South Africa to investigate a diamond smuggling operation. He then went on to solve the murder of his musician mentor, Emil Rogello. Less than a year later, Cosmo traveled to the United States where he became involved in a scandal at the Russian Legation in New York City, and even shared in a cowboy-style adventure in Texas. 
- Acting: Cosmo could act on a professional level.
- Disguise: Cosmo was a master of disguise.
- Mimicry: Cosmo could mimic most actions and voices.
- Music: He was also expertly trained to play the piano.
- This version of Cosmo (Earth-Two), including all history and corresponding appearances, was initially erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. However the ending of Convergence retroactively prevented that collapse, saving all the alternate realities, though in an "evolved" form. Even though versions of the character may have since appeared, this information does not apply to those versions.
- Cosmo employed the use of a theatrical disguise kit.
- 39 Appearances of Cosmo (Earth-Two)
- 2 Images featuring Cosmo (Earth-Two)
- Quotations by or about Cosmo (Earth-Two)
- Character Gallery: Cosmo (Earth-Two)