Martinez still had two years remaining on his existing contract but was delighted to pledge his future to the club."I feel flattered. The long relationship has always been in my mind," he said.
"The contract is for as long as we can work together in terms of fulfilling each other's ambitions.
"We have come a long way in the last 10 months and we really believe that the next three or four years are going to be vital for our football club."
The Swans were hoping to be officially crowned champions at Saturday's final home game of the season against Leyton Orient at the Liberty Stadium.
However, Leeds United's battle to have their 15-point Football League penalty overturned remains unresolved following an arbitration hearing last week and therefore Roberto Martinez's side must wait to be officially confirmed as League One winners.
"Following legal advice, the Football League can confirm that it will not present the League One trophy to Swansea City at their match with Leyton Orient on Saturday due to the ongoing arbitration hearing involving Leeds United," read a Football League statement.
"The panel in the hearing have committed to provide a verdict on or before May 1 and the league has been advised not to engage in any actions which might be misconstrued or viewed as pre-empting the arbitration process in any way.''