WASHINGTON—President Trump is blaming the Federal Reserve for holding back the economy and stock market despite the central bank’s recent decision to do two things he wanted—halt rate increases and stop shrinking its asset portfolio.

The president blasted the Fed and Chairman Jerome Powell at three meetings in the past week alone, telling Republican senators, supporters and staffers that if it wasn’t for the central bank’s past rate increases, economic output and stocks would be higher and the U.S. budget deficit would be...