The ruling overturning a lower court's move blocking the sale, and now the $21billion sale is virtually certain to succeed.
But the larger fight between Barclays and a consortium led by Royal Bank of Scotland to buy A-B-N Amro Holding will likely continue.
Bank of America spokesman Frans van der Grint called the ruling "a complete victory for us and A-B-N Amro."
Barclays has proposed an all-share merger with A-B-N worth $86 billion.
The R-B-S consortium's mostly cash offer is worth $95.6 billion but was dependent on LaSalle remaining within A-B-N.