The 23-year-old, who led the league with 1,646 receiving yards last season, has been awaiting his fate since May, when it emerged he had violated the substance-abuse policy for the second time
And the confirmation came that Gordon would miss the entire campaign, which kicks off next Thursday when the defending champion Seattle Seahawks host the Green Bay Packers.
Gordon, whose team get under way at the Pittsburgh Steelers next Sunday, said in a statement: "I'd like to apologise to my teammates, coaches, the Cleveland Browns organisation and our fans.
"I am very disappointed that the NFL and its hearing office didn't exercise better discretion and judgment in my case."
Gordon, who missed two games last season due to his first indiscretion, had hoped to avoid this fate by participating in a lengthy appeal session in front of arbitrator Harold Henderson.
However, his efforts failed with an NFL statement saying: "Appeals officer Harold Henderson has upheld the suspension for the 2014 NFL season of Cleveland Browns wide receiver Josh Gordon for violating the NFL Policy and Program for Substances of Abuse. The suspension is effective immediately."
Gordon will not be allowed to spend time at the team's facility for the duration of his ban.