A former Bank of Scotland on Union Street is now trading as Halifax after it became the first new opening for the brand in Scotland in more than a decade.
The Aberdeen branch will be followed by the launch of "flagship" Halifax outlets in Glasgow and Edinburgh by the middle of next year.
Planning permission is currently being sought from City of Edinburgh Council to convert a former retail outlet on Edinburgh's Princes Street into a Halifax branch.
Lloyds has yet to disclose the location of the preferred Glasgow site, though it is believed to be looking at the Buchanan Street and Sauchiehall Street areas.
Lloyds revealed its plans to bring the Halifax brand back to Scotland in August in response to calls from customers for a full branch service north of the Border.
The branch in Aberdeen will allow customers to service their accounts in person, and allow greater access to Halifax products such as the Reward Current Account, First Time Buyer mortgages and Children's Savings products.
Customers can also get advice on the different ways they can bank with Halifax, including online and via apps on mobiles and tablets. More Halifax transactions now take place digitally and on mobiles than via branches and cash machines.
David Nicholson, group director for Halifax Community Bank, said: "It's fantastic to bring the Halifax back to the high street. The Halifax is very much the UK's number one challenger banking brand.
"We've got strong demand from customers to be here and bring our great range of products - current accounts, mortgages and servicing - back to Scotland."
The Aberdeen branch has 18 staff and Lloyds expects its three Scottish branches to employ 75 to 80 in total.
Some two million Halifax products are held by customers in Scotland.