Alex Neil's side ended their club's dismal record of seven failed playoff campaigns thanks to goals from Elliot Embleton and Ross Stewart.
The Black Cats' promotion justified the decision to sack Lee Johnson in January and replace him with former Preston boss Neil.
After four years in the third-tier wilderness, Sunderland are finally on the up as the sleeping giants awake from their slumber.
While a return to the Premier League will not be easy for Neil's team next term, that will be the goal for a club with vast potential who last played in the top flight in 2017.
Over 45,000 Sunderland fans turned Wembley into a cauldron of noise after the red-and-white-clad hordes had taken over London landmark Trafalgar Square on the eve of the match.
Wycombe's quest for an instant return to the Championship fell at the final hurdle, meaning 40-year-old Adebayo Akinfenwa's 755th and last appearance of his career ended in disappointment.
Given their wretched history in the playoffs, where they had lost three finals and three semifinals, Sunderland arrived at Wembley haunted by the ghosts of past failures.
But they matched Wycombe's physical approach blow for blow and produced the better attacking play to run out deserved winners.
Sunderland made the breakthrough in the 12th minute when boyhood fan Embleton justified his recall with a fine run and swerving shot from 25 yards that eluded a weak attempted save from David Stockdale.
On the hour, Bailey Wright misjudged Anthony Stewart's long ball, allowing Sam Vokes a sight of goal, but the Wycombe forward hesitated and Anthony Patterson rushed out to make a crucial save.
Sunderland's promotion was sealed in the 79th minute when the influential Alex Pritchard picked out Stewart and he drilled a clinical finish in the bottom corner from the edge of the area.