He gained media attention as the winner of the first season of the reality television singing competition Happy Sunday in 2007.After signing a contract with Linfair Records, Wei released his debut EP Slowly Wait in 2009.
The following year, Wei released his eponymous debut album William Wei.
He received 4 nominations at the 22nd Golden Melody Awards and subsequently won Best New Artist.Wei released his second studio album Someone Is Waiting in 2012 and his third studio album Journey Into The Night in 2014.
The latter received 2 nominations at the 26th Golden Melody Awards and the lead single "Wolves" ("?") won him the Best Composer award.On 12 September 2015, Wei held his concert, "Free That Girl", at the Taipei Arena for the very first time.