"Today I am announcing my retirement from playing professional football," Wilshere, who last played for Denmark's Aarhus, said on Instagram.
"In truth it has been difficult to accept that my career has been slipping away in recent times due to reasons outside of my control whilst feeling that I have still had so much to give," he added.
Wilshere said he was through "an unbelievable journey filled with so many incredible moments."
The midfielder said he lived his dream, captaining Arsenal and playing for the English national team in the 2014 FIFA World Cup.
He thanked his family, friends, teammates, coaches, and staff he worked with.
Wilshere began his career at Arsenal, playing for the Gunners' youth and senior teams.
He also played for England's Bolton Wanderers, Bournemouth, and West Ham United before his move to Denmark's Aarhus in February.
He helped Arsenal win the 2014 and 2015 English FA Cups, as well as an English FA Community Shield in 2014.
Wilshere amassed 34 international caps for his native England.