He was left out of United's squad for their summer tour of the USA and Sociedad president Jokin Aperribay confirmed he wanted the youngster.
Januzaj's emergence was probably the highlight of David Moyes' ill-fated nine months in charge at Old Trafford - but since then, the Brussels-born player has seen his career massively stall.
World stock markets cheered by healthy economy; dollar firm
The big four banks rose between 0.1% and 0.7% while regional lenders Bendigo and Bank of Queensland ended up more than 1% each. Snap, the parent of photo messaging app Snapchat, dropped 4.9 per cent following a downgrade from Morgan Stanley.
Januzaj sealed his exit from United by completing his transfer to La Liga outfit Sociedad, both clubs confirmed on Wednesday night.
And the Belgium worldwide took to Instagram to post a message to United's supporters after being unveiled as a Sociedad player, choosing to only pay tribute to a section of the coaches at Old Trafford.
Bills DT Washington arrested
The Bills have been off on break since mid-June before players begin reporting for training camp, which opens July 27. Washington allegedly displayed a gun to police as officers were attempting to clear out a water park around 10 p.m.
Januzaj originally joined United as a 16-year-old from Anderlecht and scored twice against Sunderland in 2013 to cement his status as a player to watch.
Real Sociedad - ironically once managed by Moyes - finished sixth in La Liga last season and qualified automatically for the group stages of the Europa League. "Thank you to some of the coaches and staff that work at Manchester United to make it such a great club!"
Deemed good enough to take Ryan Giggs' number 11 shirt, Januzaj signed a five-year contract extension that was not due to expire until 2018.
Fatal Airbag Explosion Triggered by a Hammer
The OEM noted that 12 recall notices were sent since 2009 to the Accord's registered owners. Police photos show the metal airbag inflator exploded and shot out fragments of metal.
Rob is ESPN FC's Manchester United correspondent.