"I won," Sherman said on his Twitter account.
Sherman, a key member of the Seahawks defense, and fellow cornerback Brandon Browner were suspended last month by the NFL after positive tests that violated the league's performance-enhancing drugs policy.
Sherman appealed his suspension, saying a second cup with a broken seal had been used during his urine test, invalidating the results.
Former NFL executive Bob Wallace upheld the appeal, meaning Sherman can play in Seattle's final regular season game against the St. Louis Rams on Sunday and in the playoffs.
Browner, who did not appeal, will complete his four-game suspension in Sunday's game and also will be eligible for the postseason for the surging Seahawks.
NFL spokesman Greg Aiello said the league was reviewing the Sherman decision, but declined comment due to confidentiality provisions.
Sherman's attorney praised the decision.
"We are very pleased that the hearing officer recognized that the egregious errors that occurred with Mr. Sherman's collection required overturning the NFL's discipline," Maurice Suh said in a statement.
"Mr. Sherman provided honest testimony about a severely flawed process, and the hearing officer found him to be a credible man." (Reporting by Gene Cherry in Salvo, North Carolina, editing by Mark Meadows)
