Dublin-based C&C, which sponsors Celtic and Rangers with its Magners and Blackthorn brands, has acquired the remaining equity from shareholders Brian Calder, Chris Cosh and David Cosh.
In doing so, it has brought forward a move it had scheduled to complete within two to three years of making its initial investment in Wallaces last year.
John Gilligan, managing director of TCB, said: "We expected to do something in two to three years, but it has come forward because the partnership was pretty smooth and the people involved were all very comfortable with each other. It genuinely feels right to do it now."
Wallaces Express will be rebranded as Wallaces TCB as a result of the deal, and will seek to further develop the multi-beverage portfolio it provides the licensed trade across Scotland.
That portfolio has been extended in recent months with the addition of a 500-strong wine list, and new beers such as Caledonia Best and Heverlee.
Mr Gilligan said the full acquisition of Wallaces removes any lingering doubt among customers shared by Wallaces and Tennent's about who they were dealing with.
But he said the main prize for both parties is in gaining access to a broader range of customers.
Mr Gilligan said: "I would suggest the main benefit is that we have shared customers, but we also have a number of customers that only trade with one of us.
"We share about maybe 25% of the customers, but there are about 30% we each don't trade with. Suddenly, those doors open up because you are either a Tennent's customer or a Wallaces customer. That's the big opportunity."
C&C declined to comment on the value of the transaction, but revealed the Wallaces management team, led by Mr Calder and Chris Cosh, will remain in day-to-day charge. The two, described by Mr Gilligan as "vital to the business", had gained control of Wallaces in a management buyout in 2003.
Their relationship with TCB predates C&C's investment, with Wallaces acting as a distributor and agent for Tennent's Lager on the west coast of Scotland for several years.
The Wallaces deal is the latest in a string of investments C&C has made since acquiring TCB from AB InBev for £180 million in 2009. Since then, TCB has taken a 25% stake in Alloa-based pub group Maclay Inns, increased its lending to trade customers by more than £20m, and invested £8m in a new bottling hall, training academy and other infrastructure improvements at Wellpark.
TCB has also set up a joint venture with Williams Brothers to develop a craft brewery and centre of excellent in the Drygate area of Glasgow, close to Wellpark. Mr Gilligan pledged that C&C would continue to invest in supporting Scottish trade operators, adding: "We're not putting a number on this but it's another substantial investment in Scotland for C&C. It's [been] very productive."