The orchestra announced Wednesday that the goal had been met.
In a statement, board chairman Douglas Hagerman said the MSO board can now turn to "the big picture" - changes to permanently stabilize and capitalize the orchestra.
Individual gifts made up the largest portion of the campaign, at $2.8 million. That included 1,408 new individual donors contributing an average gift of $340.25 each, the Milwaukee Journal Sentinel reported.
In December, the MSO announced a one-time campaign to raise $5 million to pay off a $2 million shortfall, stabilize its cash flow and plan a balanced budget for its 2014-15 season.