Wo Fat made his debut appearance at the end of the episode, Hana 'a'a Makehewa (episode) where he spoke to assassin, Victor Hesse, the man responsible for killing John McGarrett, Steve's father in the Pilot (episode).
In the episode, Ke Kinohi (episode), Fat was seen playing golf with the Honolulu Yakuza's crime boss, Hiro Noshimuri when Steve and Detective Sergeant Danny Williams (2010) confronted Hiro and Hiro's brother, Koji about stealing evidence concerning the car bomb murder of Steve's mother and the kidnapping of Steve's sister, Mary McGarrett.
After the arrest of Hiro Noshimuri for arranging the theft, it is implied that Wo Fat was of some importance as he was seen being chauffeured around in a golf cart by a bodyguard.
It was not clear at this point what his role is in the local Yakuza organization until in the episode, Ne Me'e Laua Na Paio (episode) where Agent Jenna Kaye revealed to Steve about Wo Fat by showing him a picture of Wo Fat talking to Victor Hesse in prison.
Jenna told Steve that Hesse and Hiro both worked for Wo Fat and she also tells Steve about her days in the CIA where she was trying to capture Wo Fat. She found that Wo Fat was in Macao and had a CIA send a grab team to capture Wo Fat but it turned out to be a trap as the whole team was killed including Jenna's fiance, Joshua Hirsch although his fate was not disclosed until later on in the series.
At the end of the episode, Wo Fat confronted Steve in a restaurant where Steve was due to meet Jenna. Wo Fat wanted to know what Steve knew about him so far and also warned Steve not to dig to deeply into Steve's family's history because Steve might not like what he finds with the confrontation presumably leaving Steve deeply shaken.
In the Season 1 episode finale, Oia'i'o (episode), Laura Hills, Governor Pat Jameson's assistant was killed in a car bomb Wo Fat personally arranged, leaving Jameson devastated and Steve hellbent on searching for answers. Steve eventually and personally confronted Jameson by breaking into her mansion where Jameson told him that she had ordered Hill's death after she learned she was sending Steve packages with evidence from John McGarrett's investigation.
Wo Fat eventually snuck up on Steve and had him tasered, using Steve's gun to kill Jameson before fleeing the scene and making it look like Steve killed Jameson.
At the end of the episode, Steve was arrested and imprisoned for Jameson's death while Hawaii Five-0 was broken up and their Headquarters shut down.
A week after the Governor's death and Steve's arrest in the episode Ha'i'ole (episode), Chin noticed Wo Fat at Gov. Jameson's funeral.
After the funeral, Chin approached Wo Fat. His two bodyguards, Pao Dan and Wei Ling, tried to stop Chin but were defeated.
Chin told Wo Fat killed the Governor and that the truth will be out soon but Wo Fat ignored his statement and congratulated Chin on joining HPD before leaving.
Chin watched as Wo Fat and his men drove away as he glances at Wei Ling's wallet that he pick-pocketed.
After Steve was stabbed by Hesse, Danny and Chin learnt that Hesse was ordered to kill Steve by Wo Fat but purposely didn't so that Steve could escape and get Wo Fat. Hesse knew that after he killed Steve that Wo Fat was going to go for him to "tie up loose ends" before Wo Fat disappeared.
Steve eventually escaped and after he was cleared, he, Danny and Chin attempted to arrest Wo Fat. Through information in Wei Ling's wallet they were able to find out that Wo Fat was arranging an arm's deal involving ingredients for a dirty bomb at a boat harbor.
Kono was observing them but was eventually captured by Wo Fat. He interrogated her to see what she was doing here and finally had Pao Dan take Kono away presumably to be either held or executed.
Kono managed to escape and tipped off 5-0 on the arms deal. Steve, Danny, and Chin raided the boat but didn't find Wo Fat while Joe and Kono engaged the buyer in a chase before killing the mysterious buyer, finding the bomb materials as well.
Near the end of the episode, Steve learnt of a video recording showing his father, John meeting both Wo Fat and Governor Jameson but the video had no audio whatsoever. Steve was left harboring doubts, believing his father that might be dirty, remembering that Wo Fat brought up at their first meeting about not to dig too deeply into his family's past.
The closing scene of the episode showed Wo Fat leaving Halawa Prison after killing Victor Hesse, having either slashed Hesse's throat. As he entered the car, it was revealed that the car was being driven by Jenna Kaye who apparently worked for Wo Fat.
In Ka Hakaka Maika'i (episode), Joe White brought in NCIS Special Agent Kensi Blye (who is a lip reader) to try and figure out the purpose of the meeting. The only important thing she could find was the name, "Shelburne". Joe and Steve couldn't figure out the meaning of the word so Joe arranged with Steve to meet Hideki Makoto, a former Imperial Japanese fighter pilot who helped bomb Pearl Harbor and who later became John's friend.
Makoto hired John to investigate corruption in the Police Department and in politics after being fed up by both. As John investigated further he found that the Governor was actually in league with the Yakuza and Wo Fat. John couldn't act upon his findings due to threats to his family, including his wife's death.
Wo Fat later confronted Joe White in his "apartment" and Wo Fat asks Joe why he talked to people who weren't with. Joe retorted by asking what "Shelburne" was. Wo Fat was left trouble, admitting to Joe that he was surprised by how much Joe and Steve know. Wo Fat then attempted to Joe him with a gun he was carrying but Joe disarmed him.
The two men then engaged in a brutal fight in which Wo Fat used his great skill in martial arts to finally get the upper hand on the well-trained Joe. Wo Fat proceeded to strangle him but Joe ultimately freed himself and went for Wo Fat's gun, only to find that Wo Fat had fled.
In Kil'ilua (episode), Wo Fat used a local reporter, Bethany Morris as a means of giving Jenna Kaye hope that her fiance, Joshua was still alive. The reporter was later murdered afterwards and it was revealed that Jenna was working for Wo Fat because he had threatened the life of her fiance. Jenna lured Steve to North Korea where Wo Fat and his men emerged, capturing Steve.
Jenna was eventually led to where her fiance was but discovered that he was dead and realized that Wo Fat had killed Josh all along while using her as a means to get to Steve. Devastated, Jenna contacted Detective Sergeant Danny Williams (2010) and told him of what was going on while Officer Kono Kalakaua (2010) traced the call, prompting the Hawaii Five-0 team to launch an unofficial rescue operation to save Steve.
Back in Korea, Jenna took some pins from Josh's knee (pins that Josh had received in an accident) and she slipped them to Steve while also apologizing for what had happened. One of Wo Fat's men later discovered the radio, realizing that Kaye had radioed for help which had Wo Fat taking matters into his hands and killing Jenna by shooting her in the chest with an enraged Steve witnessing the killing and swearing revenge for Jenna's death.
Steve later used the pins to free himself and sought to escape but was recaptured. In the process of a transfer, Wo Fat's convoy was attacked by Lori Weston's RPG gun while Danny, Kono, Detective Lieutenant Chin Ho Kelly (2010), Joe and a few SEAL operatives from SEAL team 9 attacked Wo Fat's convoy, eventually saving Steve although Wo Fat escaped in the processed.
A few months later, with his desire to find Joe White and get answers into "Shelburne" growing stronger, Steve eventually albeit temporarily left the team some time prior to Ha'alele (episode) and the two crossover episodes with NCIS: Los Angeles, Pa Make Loa (episode) and Touch of Death (episode) which also resulted in Danny becoming the temporary team leader. (In real life, this was written into the series due to Alex O'Loughlin who plays Steve McGarrett entering rehab at the time of the three episodes in question being aired to receive supervised treatment for prescription pain medication due to a recent shoulder injury).
Wo Fat returned in Ua Hopu (episode) where after a long and lengthy gunfight, Steve finally escorted his sworn enemy to prison despite the Japanese Yakuza led by Adam Noshimuri gunning for Wo Fat, having believed that Wo Fat and Steve had killed Hiro Noshimuri, the Yakuza's original leader and also Adam's father where he told Wo Fat that prison was the place where he'd die before leaving while Wo Fat simply smiled back.
In La O Na Makuahine (episode), Wo Fat was on the verge of being transferred but the prison truck he was in was knocked off the road, resulting in Fat being freed.
It was later revealed that Frank Delano was the man responsible for breaking Wo Fat out of prison with the team striking a deal. Delano and his men would be able to get off drugs off the island in exchange for giving Wo Fat the location of Shelburne who was also revealed to Doris McGarrett, Steve's supposedly dead mother.
Wo Fat eventually confronted Doris in Steve's home and the two got in a stand-off, holding each other at gunpoint. However, Doris later fired three shots into the ground, giving Wo Fat time to escape although it's not known the event of the relationship Doris has with Wo Fat.
In Hana I Wa 'Ia (episode), Wo Fat kidnapped a congressman and was about to kill him until a chopper manned by Steve with Danny firing arrived on scene. The congressman was rescued while Wo Fat exchanged gunfire with Danny before fleeing yet again.
In Imi Loko Ka 'Uhane (episode), Wo Fat returned, disguised as a police officer and when Savannah interviewed him during the show she videotaped about the five 0, McGarrett discovered that was Wo Fat and started to shoot him but got away. Despite this, Wo Fat was severely injured during a gunfight in the jungle but Steve refused to kill him so he opted to send Wo Fat to hospital instead with prison officers guarding the room while Wo Fat lay handcuffed to the bed.
In the Season 3 finale episode, Aloha, Malama Pono (episode), Wo Fat was seen lying in a bed in a High Risk Detention Facility at an Unknown Location with Steve standing in the room, staring at Wo Fat and at the end of the episode, Fat told Steve that he was his protection because the unknown forces currently breaking down Fat's door want Wo Fat dead, ending the episode in a cliffhanger.
In Aloha ke kahi I ke kahi (episode), NLM terrorists attempt to kill Wo Fat but McGarrett saves him. Before Wo Fat is transferred to Supermax Facility in Colorado McGarrett wants an answer from Wo Fat why Doris visited him. Fat said, "She wanted to apologize to him for killing his father."
- Victor Hesse- (Deceased, killed by Wo Fat).
- Fred Durran- (Deceased, shot dead by Detective Danny Williams).
- Anton Hesse- (Deceased, shot dead by Lt. Commander Steve McGarrett).
- Sang Min- (Currently on the run, having escaped from prison).
- Wei Lyng- (Alive).
- Pao Dan- (Alive/imprisoned).
- Governor Pat Jameson- (Deceased, shot dead by Wo Fat).
- Haul Yorutt- (Deceased).
- John McGarrett- (Deceased, shot dead by Victor Hesse).
- Hiro Noshimuri- (Deceased, killed by Wo Fat).
- Wo Fat's Guard- Ki'ilua- (Deceased).
- Wo Fat's Commander- Ki'ulua- (Deceased).
- Wo Fat's Interrogator- Ki'ulua- (Deceased).
- Amilia Woods - (Deceased).
- Frank Delano- (Deceased, shot dead by Chin Ho Kelly).
- Brad Powers (alive/in custody).
- Unidentified Henchman/ driver/ sniper- (Deceased, shot dead by McGarret).
- Jenna Kaye (Deceased).