Seth Baczynski was born 26 October, 1981 in Apache Junction, Arizona, USA. He is currently fighting at 170 in the UFC. He was a cast member of TUF 11 - The Ultimate Fighter: Team Liddell vs. Team Ortiz. Baczynski currently resides in Temple, Arizona, training at Power MMA and Fitness with Ryan Bader, CB Dollaway, Aaron Simpson, and Robbie Lawler.

Early career

Baczynski began fighting in 2006, making his debut at a Rage in the Cage event. Baczynski lost the fight to Shane "Battle Cat" Johnson via knee bar submission in round one. Baczynski then won three straight fights, all for Rage in the Cage.

International Fight League (IFL)

He then signed a contract with the International Fight League. He debuted for the promotion against Brent Beauparlant, losing via decision. He then fought Dan Molina. Baczynski lost that fight and was released from the IFL.

Post-IFL

Baczynski obtained a 7–1 record after being released from the IFL. He then fought up and comer Roger Bowling, losing by KO only nine seconds into round one. Baczynski won a fight against Tom Nguyen at a Wild Bill's Fight Night 23. He was then selected to be a part of the next TUF season.

The Ultimate Fighter

Baczynski competed in the TUF season as a middleweight. Baczynski fought Court McGee. After two rounds, the judges awarded the win to McGee, sending Baczynski home.

Baczynski was given a second chance when Chris Camozzi was forced to leave due to a broken jaw. With Baczyski taking Camozzi's spot. In his first fight back he fought Team Liddell's last pick, Joseph Henle. Baczynski won the fight via three round unanimous decision.

In the quarter-final round, Baczynski faced rival team member and friend Brad Tavares. Seconds before the first round was about to end, Baczynski threw an illegal soccer kick to the head of Tavares, who was attempting to stand up. This immediately knocked Tavares out. Baczynski quickly apologized, knowing he could have seriously hurt Tavares. After discussing the matter with the doctors, Herb Dean stopped the fight and Tavares was declared the winner by disqualification, advancing him to the semi-finals.

This caused a heated argument between the coaches; Tito Ortiz and Chuck Lidell over the decision.

Ultimate Fighting Championship

Baczynski made his UFC debut in a rematch against Brad Tavares at The Ultimate Fighter: Team Liddell vs. Team Ortiz Finale. After three close back and forth rounds, Baczynski lost the fight via unanimous decision (29-28, 29-28, 29-28).

Due to his loss to Tavares, Baczynski was subsequently released from the UFC.

Post-UFC

After being released from the UFC, Baczynski was signed by Strikeforce and was scheduled to make his promotional debut at ShoMMA 10: Riggs vs. Taylor against Erik Apple. However, Apple was forced to pull out of the fight and a replacement was not named.

He then fought UFC and WEC veteran, Tim McKenzie, at Tachi Palace Fights 7. The fight was ended after McKenzie broke Baczynski arm with an attempted armbar. McKenzie was then quickly knocked out by elbows from Baczynski. 

McKenzie appealed  the result to the California State Athletic Commision. Video footage that Baczynski "may have" tapped out and once he was released proceeded to strike McKenzie until the stoppage for the win. The referee did not stop the fight based on Baczynski's hand movement. Most likely he was placing his hand on McKenzie's chest to get an early feel for if he would try roll him over, putting him in a much worse position that he would need to counter, and any shaking was due to his arm being broken, as it was not a clear tap. 

It currently stands that Baczynski won the fight via knockout.

On 9 April, 2011, Baczynski became the interim Ringside MMA welterweight champion when he TKO formerly undefeated Alex Garcia at Ringside MMA 10 at 2:44 in Round 2.

Return to UFC

Baczynski returned to the UFC facing Clay Harvison on 17 September, 2011 at UFC Fight Night 25, replacing an injured DaMarques Johnson. He won the fight via submission (Rear Naked Choke) at 1:12 in Round 2. Baczynski again stepped-in on short notice to fight Matt Brown on 19 November, 2011 at UFC 139. He won the fight via submission (Guillotine Choke) at 0:42 in Round 2. Baczynski fought Lance Benoist on 8 June, 2012 at UFC on FX 3. Baczynski defeated Benoist via split decision.

Baczynski next faced Simeon Thoresen on 22 September, 2012 at UFC 152. Baczynski was surprisingly being out striked by Thoresen throughout the fight until he landed a big punch that instantly knocked Thoresen out late in the first round at 4:10. Baczynski was expected to face Kyle Noke on 15 December, 2012 at UFC on FX 6. However, Noke pulled out of the bout citing a shoulder injury and was replaced by Mike Pierce. He lost the fight via unanimous decision 

Baczynski fought promotional newcomer Brian Melancon on 6 July, 2013 at UFC 162. He lost the fight via knockout due to ground and pound at 4:59 in Round 1. It was unlikely Baczynski could have recovered for a victory in Round 2, if he could've lasted one more second. Baczynski faced Neil Magny on 6 November, 2013 at UFC Fight Night 31. He won the back-and-forth fight via unanimous decision. Baczynski faced Thiago Alves on 10 April, 2014 at UFC on Fox 11. He lost the fight via unanimous decision. Despite the loss, this fight earned Baczynski his first Fight of the Night bonus award. This was his first fight bonus in his career.

The Ultimate Fighter

Episode 1 - Loss to Court McGee unanimous decision (29–28, 29–28, 29–28) after two rounds.

Episode 3 - Replaced injured Chris Camozzi

Episode 7 - defeated Joseph Henle via unanimous decision after three rounds.

Episode 9 - Brad Tavares defeated Baczynski via disqualification (illegal soccer kick) at the end of the first round.