Dottin (52 not out off 37 balls) finished the innings with a flourish as Adelaide made 5-147, a score which looked a little below par.
She was uncharacteristically restrained for most of her innings but boosted the Strikers score by smashing two sixes and two fours in the last three overs.
Dottin (2-30 off 4) then bowled a double-wicket maiden early in the Sixers chase as they lost 4-6 and tumbled to 4-16 in the sixth over.
Adelaide had lost their two previous finals and it was the third time in four years they had made the season decider.
"This one has been a long time in the making which makes it extra special when you get so close so many times," skipper Tahlia McGrath said.
The Strikers openers Katie Mack (31 off 26) and Laura Wolvaardt (15 off 16) made an excellent start, putting on 51 from the first 6.2 overs but fell In successive overs.
Dottin had a decent slab of luck in her influential innings.
She was dropped on one at backward point and was caught twice off a no-ball, the first delivery was ruled too high and the second call was for overstepping.
"I got some luck so it was good for me to capitalise on it," said Dottin, who rated it among her best five innings.
"I was a bit nervous once wickets started to fall, it was on me, I'm the one that is actually there to hit the big ones, so I said to myself 'I have to stay to the end no matter what' for us to get a competitive total on board."
Dottin and McGrath (24 off 21) added 44 for the third wicket but the Strikers lost 2-7 in their power surge.
Dottin was uncharacteristically restrained for most of her innings, but boosted the Strikers score by smashing two sixes and two fours in the last three overs.
England spinner Sophie Ecclestone (2-19 of 4) was the standout bowler for the Sixers.
The Sixers' innings started 15 minutes late in front of 6478 spectators.as the umpires waited for the sun to set.
And in a dramatic second over of the innings bowled by Brown, Suzie Bates was dropped twice and Alyssa Healy was caught at square leg.
Dottin then struck twice in four balls, having Bates caught at deep midwicket and player-of-the-tournament Ash Gardner taken at midwicket for a fourth-ball duck.
The collapse continued with Erin Burns stumped at the second attempt by Tegan McPharlin off Jemma Barsby.
"It always stings not to win a final but equally extra special for the Strikers to defend that total," Sixers star Ellyse Perry said.
"They've been a great team for a number of years and thoroughly deserve victory.
"We probably lost a few too many wickets early."
