McEwen will be unavailable for the Knights' next game against St George Illawarra in round 16 and also receives a $5000 suspended fine from the club.
The 21-year-old second-rower, who is having a breakout season, was charged police for low-range drink driving and driving on a suspended licence on May 22.
"I am deeply ashamed of my actions," McEwen said in a statement.
"There is no justification for what I did, getting behind the wheel with alcohol in my system was irresponsible, dangerous, and completely beneath the standards I hold myself to as a person and as a professional footballer.
"I'm fully aware of the trust the Newcastle Knights have placed in me, and I let the club, my teammates, and everyone who supports this team down.
"The NRL is a privilege, and I do not take lightly the responsibility that comes with it ... I offer my unreserved apology."
McEwen reported the incident to the Knights after it occurred, with the club then referring the matter to the NRL integrity unit.
He is due to face court later this month.
The seventh-placed Knights have been one of the NRL's biggest improvers this season, having placed last in 2025.
McEwen has become a mainstay of the team on the right edge, playing all 13 games since Justin Holbrook took charge as coach.
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