The US State Department added Abdelilah Himich, also known as Abu Suleiman Al-Faransi, to its list of "specially designated global terrorists."
The designation said he founded 300-strong Islamic State "European foreign terrorist fighter cell" and reportedly helped plan the deadly attacks.
US and French officials describe Himich as 27 or 28 years old and as a Moroccan-born French citizen who served six months in the French Foreign Legion.
In November last year, Islamists attacked the Bataclan concert hall in Paris, sprayed cafes with bullets and set off bombs outside a soccer match.
In all 130 people died, and hundreds more were hurt.
Then in March, suicide bombers attacked Brussels airport and a metro station, killing 32 more.
According to the State Department, Himich helped plan these attacks, as well as providing fighters for Islamic State operations in Iraq and Syria.
The designation also blacklisted Abdullah Ahmed al-Meshedani, who allegedly houses fighters, answering to IS leader Abu Bakr al-Baghdadi.
It also named Basil Hassan, who is accused of shooting and wounding Lars Hedegaard. a 70-year-old Danish historian, in February 2013.