Maggert turned professional in 1986. He was Player of the Year on the Ben Hogan Tour (now the Nationwide Tour) in 1990, and has been a member of the PGA Tour since 1991. He has won three times and finished runner-up 15 times on the PGA Tour, in addition to winning several other professional tournaments. He has represented the United States in the Ryder Cup three times and in the Presidents Cup once.