Seagal, who became a Russian citizen in 2016, is a close friend of Russian President Vladimir Putin.
The announcement comes with Russia-US ties at a low ebb, over long-standing conflicts in Syria and Ukraine and allegations of Russian interference in the 2016 US presidential election, which Moscow rejects.
Seagal was also granted Serbian citizenship in 2016 after several visits to the Balkan country, the BBC reports.
It said Seagal would "facilitate relations between Russian Federation and the United States in the humanitarian field, including cooperation in culture, arts, public and youth exchanges".
This will cover "culture, art, public and youth exchanges, among other things", the Russian Foreign Ministry said on its Facebook page. Seagal, who is known for his affinity for martial arts, will receive no salary in his new role.
"I've always had a very strong desire to do all I can to help improve Russian-American relations", RT quoted Seagal.
In the interview, Seagal also praised Putin as "a great world leader" and a "brilliant tactician".
Seagal has been closely connected to Putin over the past few years, even attending the Russian president's swearing-in ceremony after this year's Russian election earlier this year.
According to Seagal's own website, the 66-year-old has been a regular visitor to Russian Federation for over a decade. His movies, including such titles as "Under Siege" and "Sniper: Special Ops", are popular with Russian audiences.
Seagal's grandmother was born in Vladivostok, and the actor and Putin share a passion for martial arts.