The ruling lifts a freeze implemented by a lower court, allowing the president to access about $2.5 billion from the Defense Department.
Those funds are expected to be used towards construction of parts of the wall in California, Arizona and New Mexico.
President Trump touted the ruling as a “big win” for border security.
The justices were largely split between along ideological lines.
The court’s five conservative justices gave the administration the greenlight to begin work on four contracts it has awarded using Defense Department money. The court’s four liberal justices wouldn’t have allowed construction to start.
The case the Supreme Court ruled on began after the 35-day partial government shutdown that started in December of last year. Trump ended the shutdown in February after Congress gave him approximately $1.4 billion in border wall funding. But the amount was far less than the $5.7 billion he was seeking, and Trump then declared a national emergency to take cash from other government accounts to use to construct sections of wall.
The money Trump identified includes $3.6 billion from military construction funds, $2.5 billion in Defense Department money and $600 million from the Treasury Department’s asset forfeiture fund.
The case before the Supreme Court involved just the $2.5 billion in Defense Department funds, which the administration says will be used to construct more than 100 miles of fencing. One project would replace 46 miles of barrier in New Mexico for $789 million. Another would replace 63 miles in Arizona for $646 million. The other two projects in California and Arizona are smaller.
The Associated Press contributed to this story.