The San Marco Italian Restraunt backed entry drove away from reigning series winner Adam Beechey (Donut King) to win the 14 lap race by almost five seconds.
Tony Bates (Sports Alive), Matthew Chick (Renaissance Homes) and Ross McGregor (Souther Star Windows) rounded out the top five.
After showing strong speed at the opening rounds of the season, the win was a relief for Hayes.
“It's fantastic to break through, finally,” he said.
“We've had race winning pace for several rounds now but one thing or another has got in the way of us winning before now, so it's great to finally get one under the belt.
“They say that once the first one is out of the way it gets easier from here so I hope that is very much the case!”
Hayes had an early dice with Beechey and leader Marcus Zukanovic (Action Racing) that saw the trio three-wide down the straight as Zukanovic peeled off to serve a drive-through penalty for rolling at the start. The Fujitsu V8 Supercars racer would eventually finish seventh, the last of those to complete the race.
From the front row, Danny Buzadzic (Western General Body Works) led the field away with a good start but pole sitter Zukanovic quickly slipped past and asserted himself in front.
Meanwhile, Geoff Emery (NDD) and Chris Stevenson (Aerial Motors) made contact exiting the Turn 9 hairpin on Lap 2, the five-time series winner turned into the fence and out of the race.
Buzadzic joined Emery in retirement a lap later – dropping out of the race from the lead in the most unusual of circumstances.
The interior rear-view mirror of Buzadzic's Commodore became dislodged early in the race and fell into the drivers foot-well, becoming stuck across the brake and throttle pedals – leading to a trip into the runoff at Turn 11.
Hayes and Beechey fought for the lead on Lap 3, but once Hayes had slipped past at turn two the race was all but over.
The Shannons Nationals presented by Hi-Tec Oils event at Eastern Creek Raceway will feature a second 14 lap Commodore Cup race tomorrow, with the action streamed live via itvlive.com.au.