He is being replaced on an interim basis by Michiel J. Herkemij, whose experience includes five years in Heineken with responsibility for, among other things, its operations in Mexico and Nigeria.
The search for a permanent CEO has already begun.
Lousada was appointed to the chief executive role in January 2014.
Prior to taking the position, Lousada had been marketing director at Carlsberg for two years. Previous experience included stints at St Ivel, Best Foods and Budweiser.
Carlsberg's senior VP for Western Europe, Jørn Tolstrup Rohde, said: After careful evaluation, we have decided a new type of leadership is required to take Carlsberg UK forward. We thank James for all his efforts while leading Carlsberg UK through a period of many changes during the last two years.”
Lousada commented: “The time is now right for a new direction within Carlsberg UK and to have a change in leadership to deliver that. I have thoroughly enjoyed my time leading a dedicated and committed team that strives every day to put the customer at the heart of everything they do.”
Lousada’s departure follows swiftly on that of group deputy CEO and CFO Jorn P. Jensen, who left the company at the end of September.
Carlsberg reported disappointing half-year results over the summer with the UK, in particular, struggling.
The company reported sales volumes across Western Europe as a whole down by 1%. However, in the UK volumes fell by 6%, while the UK market only contracted by 4%.
This was despite Lousada’s decision earlier this year to increased Carlsberg’s UK marketing budget by 500% to £12 million.
Carlsberg also made the news recently after Tesco decided to delist its products as part of the multiple retailer’s own aggressive plans to return to growth.