Johnson has been deployed by boss David Moyes in both right-back and left-back roles whenever first team regulars were unavailable for selection.
The 22-year-old has caught the eye with his performances for the Hammers this season and a number of rival Premier League clubs have registered interest in acquiring his services.
Liverpool are among Johnson’s admirers, while Antonio Conte’s Tottenham, who failed with their efforts to sign a new right wing-back in January, and Arsenal, have been monitoring his progress at the London Stadium.
But West Ham see Johnson playing a key role at the club in the long-term and were trying to tie him down on fresh terms, although they were unable to agree on a new deal with the player.
The full-back’s deal was set to expire in the summer, but David Moyes’ side had an option to extend his stint by two years and they have opted to trigger that clause.
Johnson will receive a rise in his wages having seen his contract extended, which will now only expire in the summer of 2024.
The defender is understood to be happy at West Ham and could be back in the starting eleven at the weekend in their Premier League clash against Wolverhampton Wanderers, with first choice right-back Vladimir Coufal doubtful for the game.
