"You have to make the back grid a good result and I picked up lots of spots," Smith said.
A good second heat had him just two points off the lead for the third and deciding race, which featured a number of red light stoppages.
"All those reds were starting to freak me out. But I just had to chill out and race hard."
Smith took the race win and knew immediately he had done enough for the overall title.
"I knew which cars I had to beat, and by how much, so yeah, it was a good feeling," he said.
He will not be able to defend his title in 12 months' time, as he will be too old to race in the youth class.
Smith finished four points clear of Tauranga's Luke McClymont, and Taranaki racer William Hart was another three points back in third place overall.
The race meeting also included a Junior Championship, for 12 and 13-year-olds, which saw local racer Terence Dorrell finish on the podium in third place, just one point behind the winner Louis Redshaw from Palmerston North.
Redshaw was tied for first with clubmate Cody Hodge, but the Hodge team was unable to make the track in time for their runoff, and had to settle for second place.
The next race meeting at TWS Paradise Valley Speedway is on Saturday, March 10 and includes the Bay of Plenty Championships for superstocks and street stocks, as well as the crowd favourite demolition derby.
Tubby Norriss Memorial Ministocks in Paradise results
Senior Youth:
1st - Damon Smith (Wellington)
2nd -Luke McClymont (Tauranga)
3rd - William Hart (Taranaki)
Junior Youth:
1st - Louis Redshaw (Palmerston North)
2nd - Cody Hodge (Palmerston North)
3rd - Terence Dorrell (Rotorua)