The Freedom first posted 163-5 from their 20 overs after winning the toss.
Australian opener, Matthew Short, did the bulk of the scoring for Washington with a 50-ball 80 including 10 fours and three sixes.
He was supported by hic countryman and Freedom Captain, Moises Henriques, who hit 21 and Mukhtar Ahmed who scored 20.
South African quick, Gerald Coetzee, took 2-26 from his four overs for the Super Kings.
Texas, in their chase, were reeling at 78-6 at one point before Bravo gave them a glimmer of hope with some fireworks.
The 39-year-old hit five fours and six sixes in his innings that took just 39 balls.
In the end, they fell agonizingly short of their target at 157-8 after 20 overs.
Akeal Hosein took 2-25 off his four overs for the Freedom while Marco Jansen took 2-31 from his four.
The Super Kings managed to post just 126-9 in their 20 overs after winning the toss and choosing to bat first.
Daniel Sams hit 26* while Devon Conway and Cody Chetty each hit 24. Those were the only Super Kings batsmen to reach double figures as Andrew Tye took 3-32 and Imad Wasim grabbed 2-23 for the Orcas.
Quinton De Kock then led the successful chase for the Orcas with an unbeaten 50-ball 88 including 10 fours and four sixes.
He was well supported by Shehan Jayasuriya who hit 31* as Seattle needed just 15 overs to reach 127-1 and secure a spot in the final.
Their opponents will be determined when the Super Kings face MI New York, who beat the Washington Freedom by 16 runs in the Eliminator on the same day, on Friday.
MI New York made 141-7 off their 20 overs after being put in to bat by the Freedom.
Dewald Brevis, who played because of an injury sustained by Captain, Kieron Pollard, in their last game, led the way with 57 off 41 balls including four fours and three sixes.
Saurabh Netravalkar took 2-25 for the Freedom.
Washington were then restricted to 125-9 from their 20 overs despite 28 from Marco Jansen and 24 from Andries Gous.
Trent Boult led the charge with 4-20 while Nosthush Kenjige took 2-19 for MI New York.
The Orcas restricted their opponents to 144-7 off 20 overs after winning the toss and electing to field.
Akeal Hosein led the way with the bat for the Freedom with an unbeaten 22-ball 33 including a four and a pair of sixes. Earlier, Andries Gous made 28 and Captain, Moises Henriques, made 24 against a pair of wickets, each, from Wayne Parnell and Harmeet Singh.
The Orcas then needed 19.4 overs to reach 148-5 and secure victory. Quinton De Kock led the way with 48 off 37 balls including three fours and as many sixes. All-rounder, Imad Wasim, finished unbeaten on 43 from 38 balls. Shimron Hetmyer contributed 23.
MI New York held the Freedom to a respectable 160-6 after winning the toss and electing to field first.
Glenn Phillips hit a 35-ball 47 while Captain, Moises Henriques, hit 32 off 30 balls for Washington.
New York skipper, Kieron Pollard, was amongst the wickets with 2-33 from his four overs.
Nicholas Pooran then starred with an unbeaten 62 as MI New York needed only 15.3 overs to reach 161-2.
The left-hander faced 33 balls and struck four fours and six sixes on his way to his first fifty of the competition.
Pooran was well supported by openers Monank Patel, who hit 44 off 29 balls, and Shayan Jahangir, who made 29. Pollard was at the crease alongside Pooran in the end, finishing 21* off just 10 balls.
The Seattle Orcas and Washington Freedom have each already secured spots in the playoffs with three teams battling for the remaining two spots.
MI New York, who play the Orcas in their last game, will be in with a win or if they avoid a heavy defeat.
The Texas Super Kings and San Francisco Unicorns are the other teams in contention for a spot and they will be facing each other in a winner-take-all clash on Monday.
The Freedom won the toss and put the Knight Riders in to bat. The decision looked like the right one, early, when Washington had the Knight Riders reeling at 68-4 in the 11th over before Russell came to the wicket.
The all-rounder needed just 37 balls to hit 70*, his second fifty in the tournament. The Jamaican hit six fours and as many sixes. He was supported well by Rilee Rossouw who hit 41 off 30 balls including four sixes.
In the end, LA amassed a respectable 175-7 from their 20 overs. Freedom Captain, Moises Henriques, took 3-26 off three overs while Marco Jansen took 2-29 off four.
The ensuing chase was an all-round batting effort from the Freedom. They needed only 18.1 overs to overhaul LA’s total, eventually finishing on 177-4.
Openers Matthew Short and Andries Gous led the way with scores of 43 and 40, respectively. Short’s innings lasted 35 balls and included three fours and a six while Gous needed just 15 balls and hit five fours and two sixes.
Glenn Phillips also made a good contribution with 29 while Obus Pienaar hit 26. Knight Riders skipper, Sunil Narine, was their most economical bowler with 1-20 from his four overs.
The Knight Riders are still winless in the competition with only one match left to play.
Unicorns captain Corey Anderson won the toss and put the Freedom in to bat, a decision he was made to regret in the end as Washington piled up 207-5 from their 20 overs.
Captain Smith starred with a 52-ball 88 including seven fours and six sixes while Maxwell made 40 off 22 balls including one four and four sixes against 2-35 off four overs from Pat Cummins.
The Freedom then produced a dominant performance with the ball as well, dismissing the Unicorns for 111 in 16 overs to claim the title.
Tail-ender Carmi le Roux was the highest scorer in the innings with 20* as Rachin Ravindra and Marco Jansen took 3-23 from four overs and 3-28 from four overs, respectively.
Andrew Tye was also excellent with 2-12 from his two overs.
The Freedom are rightfully champions having suffered only one loss all season.
Full Scores:
Washington Freedom 207-5 off 20 overs (Steve Smith 88, Glenn Maxwell 40, Pat Cummins 2-35)
San Francisco Unicorns 111 all out off 16 overs (Carmi ls Roux 20*, Rachin Ravindra 3-23, Marco Jansen 3-28)
