• 
  Adam Shaheen

   Winston Churchill
• 
  Fred Kennedy

   Albert Einstein
• 
  Hayden Finkelshtain

   Nikola Tesla
• 
  Brett Jubinville

   Sigmund Freud
• 
  Matt Servo

   Charles Darwin
• 
  Sasha Bogolyubova

   Marie Curie (1 episode, 2015)
• 
  Ajay Fry

  3 episodes, 2017
• 
  Hedy Gregor

  3 episodes, 2017

• 
  Tom Park

   Carl Jung / ...
• 
  Hedy Gregor

   Marie Curie
• 
  Laurel Dalgleish

  Additional Characters
• 
  Yuri Gorbachow

  Russian Narrator
• 
  Joe Ciaravino

  Thomas Edison
• 
  Neil deGrasse Tyson

  Self
• 
  Martin Watson

  King Gustaf V

• 
  Adam Hines

  Charles Darwin
• 
  Caitlin Major

  Additional Characters
• 
  Steven Shanahan

  The Pope
• 
  Aurora Stamm

  Boys Choir