Tom Clancy's Splinter Cell: Double Agent
38 Achievements
1,000
Xbox 360
Xbox One
Xbox Series
Professional Ninja
Completed solo mode on Hard difficulty
40
How to unlock the Professional Ninja achievement in Tom Clancy's Splinter Cell: Double Agent - Definitive Guide
Just complete the entire story mode on Hard and this wil unlock. I suggest starting your first game on Hard so that you don't have to pester yourself with having to go back again and beat the entire game over.
This guide was translated automatically.
You can start right away on this difficulty. Enemies kill you quickly, so maximum stealth.