Michael Yuhasz scored a goal and assisted on another for Brighton. Lucas Morgan also had a goal and an assist, and Daniel Bosio had an assist for the Bulldogs.
Carson Gatt scored for Catholic Central (22-8 overall record).
The Bulldogs (28-2-1) won 4-1 against Detroit U-D Jesuit in the semifinals Friday night at Compuware Arena in Plymouth.
Brighton defeated Grosse Pointe North 4-3 to win last year's state championship game.
The Shamrocks have won seven state titles since 2000, most recently in 2010, according to the MHSAA website.
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