With two lengthy title reigns in the space of two years, Lethal had established himself as a dominant member of the JAPW roster by 2005, and he began challenging for the JAPW Heavyweight Championship, which had been held by Dan Maff since December 2003.
On January 29, 2005, at Wild Card, Lethal pinned Maff in a title match, but the decision was overturned by crooked referee Sean Hanson.
In March 2005, Maff left JAPW and retired from wrestling following an argument with Homicide, thus vacating the JAPW Heavyweight Championship.
Lethal was awarded the Heavyweight Championship on March 26 at Caged Fury 2 held in the ECW Arena in Philadelphia, Pennsylvania, but he refused to accept it, claiming that he wanted to "earn" the title.
JAPW mainstay Homicide then challenged Lethal to an impromptu match for the vacant title, which Homicide won.
Lethal finally won the JAPW Heavyweight Championship on May 21 in Braintree, Massachusetts, at Braintree Invasion defeating Homicide, Kevin Steen and Samoa Joe in a four-way match by pinning Homicide following a diving headbutt.

Lethal defeated Steve Corino on June 4 at HomeComing with his father in his corner, but, after the match, Corino and Ricky Landell handcuffed Lethal to the top rope and attacked his father with Corino placing him in a crossface.
This led to a six-man tag match on July 16, at Gored pitting Lethal and his father against Corino, Landell and Landell's manager, Rick Silver.
Lethal and his father were outnumbered, but managed to pull off a win at the last minute after Lethal's mother introduced their partner, the returning Charlie Haas.
After Haas attacked Lethal during the post-match celebrations, a title match was booked between Haas and Lethal for Haas of Pain held on September 10, which was won by Lethal.
On October 22 at 8th Year Anniversary Show Lethal ended his feud with Corino by defeating him for the title in a Dog Collar match with help from Tommy Dreamer.

Lethal's next feud would be with The D-Factor's Rhino, who, on November 12, 2005, at Fall Out, assaulted him following his successful title defense against B-Boy.
On January 7, 2006, at Wild Card II, Lethal lost the JAPW Heavyweight Championship to Rhino, who won the bout after giving Lethal a Rhino Driver through a table from the top rope.
Lethal tried twice to regain his title, first on February 18, 2006, in a three-way match which also included Teddy Hart, and then on May 20, 2006, but was unsuccessful both times at regaining the title.
After unsuccessfully going after the JAPW Light Heavyweight Championship held by Frankie Kazarian, Lethal and former rival Azrieal managed to win the JAPW Tag Team Championship by defeating the champions The Outcast Killaz (Oman Tortuga and Diablo Santiago) and The S.A.T. (Jose and Joel Maximo) in a three-way dance on October 28, 2006, at 9th Year Anniversary Show, held in Rahway, New Jersey.
On June 9, 2007, at Back to Business, The Latin American Xchange of Homicide and Hernandez defeated Lethal and Azrieal for the titles.

At the beginning of 2009 Lethal proclaimed that it was his destiny to win back the JAPW Heavyweight title, held by Kenny Omega.
On February 28, 2009, in Jersey City, at Jersey City Rumble Lethal won a 21-person Jersey City Rumble to earn the right to challenge for Omega's title that same night.
In the end, Lethal pinned Omega with the flipping release dragon suplex after Omega's associate Dan Maff turned on him, to win the JAPW Heavyweight Championship for the second time.
During the match Maff had also attacked Lethal and that lead to a Championship match between the two on March 28, at Unfinished Business, in which Lethal managed to retain his title.
Lethal defeated Maff again on April 18 at International Invasion, but only after Trent Acid interfered in the match.
Their feud ended on June 27 in Jersey City, at Caged Destiny, when Maff defeated Lethal for the title inside a steel cage.
Lethal has not made any appearances for JAPW since.
With two lengthy title reigns in the space of two years, Lethal had established himself as a dominant member of the JAPW roster by 2005, and he began challenging for the JAPW Heavyweight Championship, which had been held by Dan Maff since December 2003. On January 29, 2005, at Wild Card, Lethal pinned Maff in a title match, but the decision was overturned by crooked referee Sean Hanson. In March 2005, Maff left JAPW and retired from wrestling following an argument with Homicide, thus vacating the JAPW Heavyweight Championship. Lethal was awarded the Heavyweight Championship on March 26 at Caged Fury 2 held in the ECW Arena in Philadelphia, Pennsylvania, but he refused to accept it, claiming that he wanted to "earn" the title. JAPW mainstay Homicide then challenged Lethal to an impromptu match for the vacant title, which Homicide won. Lethal finally won the JAPW Heavyweight Championship on May 21 in Braintree, Massachusetts, at Braintree Invasion defeating Homicide, Kevin Steen and Samoa Joe in a four-way match by pinning Homicide following a diving headbutt.
Lethal defeated Steve Corino on June 4 at HomeComing with his father in his corner, but, after the match, Corino and Ricky Landell handcuffed Lethal to the top rope and attacked his father with Corino placing him in a crossface. This led to a six-man tag match on July 16, at Gored pitting Lethal and his father against Corino, Landell and Landell's manager, Rick Silver. Lethal and his father were outnumbered, but managed to pull off a win at the last minute after Lethal's mother introduced their partner, the returning Charlie Haas. After Haas attacked Lethal during the post-match celebrations, a title match was booked between Haas and Lethal for Haas of Pain held on September 10, which was won by Lethal. On October 22 at 8th Year Anniversary Show Lethal ended his feud with Corino by defeating him for the title in a Dog Collar match with help from Tommy Dreamer.
Lethal's next feud would be with The D-Factor's Rhino, who, on November 12, 2005, at Fall Out, assaulted him following his successful title defense against B-Boy. On January 7, 2006, at Wild Card II, Lethal lost the JAPW Heavyweight Championship to Rhino, who won the bout after giving Lethal a Rhino Driver through a table from the top rope. Lethal tried twice to regain his title, first on February 18, 2006, in a three-way match which also included Teddy Hart, and then on May 20, 2006, but was unsuccessful both times at regaining the title. After unsuccessfully going after the JAPW Light Heavyweight Championship held by Frankie Kazarian, Lethal and former rival Azrieal managed to win the JAPW Tag Team Championship by defeating the champions The Outcast Killaz (Oman Tortuga and Diablo Santiago) and The S.A.T. (Jose and Joel Maximo) in a three-way dance on October 28, 2006, at 9th Year Anniversary Show, held in Rahway, New Jersey. On June 9, 2007, at Back to Business, The Latin American Xchange of Homicide and Hernandez defeated Lethal and Azrieal for the titles.
At the beginning of 2009 Lethal proclaimed that it was his destiny to win back the JAPW Heavyweight title, held by Kenny Omega. On February 28, 2009, in Jersey City, at Jersey City Rumble Lethal won a 21-person Jersey City Rumble to earn the right to challenge for Omega's title that same night. In the end, Lethal pinned Omega with the flipping release dragon suplex after Omega's associate Dan Maff turned on him, to win the JAPW Heavyweight Championship for the second time. During the match Maff had also attacked Lethal and that lead to a Championship match between the two on March 28, at Unfinished Business, in which Lethal managed to retain his title. Lethal defeated Maff again on April 18 at International Invasion, but only after Trent Acid interfered in the match. Their feud ended on June 27 in Jersey City, at Caged Destiny, when Maff defeated Lethal for the title inside a steel cage. Lethal has not made any appearances for JAPW since.
Jay Lethal