Bruce joined Bury on non-contract terms earlier this month, scoring against Wigan on his debut.
However, he has now switched to the Latics on deadline day having previously spent the second half of last season on loan at the DW Stadium.
"Alex's experience will be a great asset, on and off the field," manager Paul Cook told the club's official website.
"He can play in a number of positions, he's seen it and done it in football, and we are really pleased to have him join the group."
Bruce could make his second debut for Wigan against Shrewsbury Town after the international break.