Walker, who is younger than newly crowned snooker world champion Ronnie O'Sullivan, won three frames on the spin to deny White a fourth title and seal a memorable 5-4 victory.
The 46-year-old certainly didn't make things easy for himself throughout the tournament, as he claimed the seniors crown following a series of impressive comebacks.
Walker had to fight back from 2-0 down against Ken Doherty to win the quarter-final, before dethroning the defending title holder David Lilley in similar fashion, coming back from 3-0 down to enjoy a thrilling 4-3 success.
His opponent in the showpiece was the three-time winner of this tournament and six-time world championship runner-up, Jimmy White.
The 60-year-old rolled back the years as he produced breaks of 138 and 132 on his way to the final.
The Whirlwind enjoyed some of his best form in years as he lost just one frame in the earlier rounds, beating Wael Talat 3-0, Rory McLeod 4-1 and Peter Lines 4-0.
White then got off to a strong start in the final as he took the opening frame with a 64 break. The Londoner continued his momentum as he carved out a 3-1 lead going into the mid-session interval.
Walker responded upon resumption and produced an encouraging break of 72. However, White restored his advantage and moved within one frame of the title as he took a 4-2 lead.
Having already produced a number of impressive comebacks, Walker didn't seem phased by the challenge. In fact, he quickly found his groove and went about cutting the deficit.
The Welshman sensationally levelled the score before sealing the title with a clearance of 83 in the deciding frame.
Speaking after the win, Walker told the BBC: "It's a dream come true. There is a lot of pressure out there. I wanted to win, Jimmy wanted to win. It is a title playing at the Crucible.
"Everybody thinks it is easy when they see Ronnie (O'Sullivan), John Higgins and Mark Williams playing. They don't miss anything, but this game is not that easy.
"I'm absolutely over the moon," he added after becoming just the 11th different winner of the prestigious event.