The 24-year-old midfielder plies his trade with Swedish second-tier side GIF Sundsvall and is eligible to play for the Republic of Ireland through his father, former Örebro SK manager Patrick Walker.
His progression to the final of the talent show gained global media attention after a few of his games were moved to avoid a clash with his television commitments.
"This is totally amazing. I just feel pure joy," Walker said after his win.
The 24-year-old ball-playing heartthrob has built up a dedicated following in his advance to the finals of the TV4 show and his life story has been a regular feature of articles in the Swedish and international media.
Aside from his exploits at the heart of GIF Sundsvall's team, which narrowly missed promotion to Sweden's top flight in November, the story of Walker's dice with death following blood poisoning five years ago won the hearts of Sweden's teenage hordes.
"He was close to death and it was a very shocking period for him and the whole family," Walker's father Pat told The Local in October.
The illness temporarily ground Walker's promising football career to a halt. Walker was on heavy medication for six months and said in a recent interview with The Emerald Exiles that his condition was "very critical" before he finally recovered.
His football career has taken in spells with top flight clubs Assyriska and AIK and he is an established member of his current side, presenting something of a dilemma for the newly crowned crooner.
Walker won Friday's final at Stockholm's Annexet arena with renditions of ”Say” (John Mayer) and ”Where the Streets Have No Name” (U2), beating off the challenge of Elin Bergman who sang ”Happyland” (Amanda Jensson) and ”Raise your glass” (Pink).
Both artists performed ”Belong”.
The final of Swedish Idol's ninth season was attended by Robbie Williams and The Fooo.