On May 2, 2015, at Chaos In Cameron II, he defeated C. W. Anderson and his mentor Matt Hardy in a triple threat match to win the vacant OMEGA Heavyweight Championship.

[7] He dropped the title to Hardy in a triple threat match including Ethan Carter III on November 2, at Loco In Joco 3.

[6] Lee made his debut with Pro Wrestling Guerrilla (PWG) on March 28, 2014, at Mystery Vortex II, losing to Andrew Everett in a three-way match also involving Cedric Alexander.

[10] At Eleven on July 26, he scored an upset victory on three-time PWG World Champion, Kevin Steen, in his farewell match for the company.

[11] Lee participated in the 2014 Battle of Los Angeles tournament, defeating Alexander in the first round and Michael Elgin in the quarter-finals, before losing to Johnny Gargano in the semi-finals.

[15] On May 22, Lee and Everett defeated The Beaver Boys (Alex Reynolds and John Silver) in the finals of the 2015 DDT4 tournament to win the PWG World Tag Team Championship.

[17] On July 24, at Pro Wrestling Guerrilla's 12 year anniversary show, Threemendous IV, Lee defeated Tommaso Ciampa.

[19] On Night 2, he, Biff Busick and Andrew Everett lost to Mount Rushmore 2.0 (The Young Bucks and Super Dragon) in a six-man Guerrilla Warfare match.

[29] On the September 2 episode of Impact Wrestling, Lee and Myers defeated The Wolves in a rematch to win the TNA World Tag Team Championship after interference from Sonjay Dutt.

[32] After a four-month hiatus, Lee returned on the February 2, 2016 episode of Impact Wrestling, winning the TNA X Division Championship from Tigre Uno with help from his new manager, Gregory Shane Helms.

[39] On the February 2, 2017 episode of Impact Wrestling, Lee defeated DJZ in a ladder match to win the title for the second time.

[41] On the April 20 episode of Impact Wrestling, Lee lost the X Division Championship to Low Ki in a six-way match that included Everett, Dutt, Dezmond Xavier and Suicide.

[46] On the September 14 episode of Impact!, Lee formed an alliance with Caleb Konley, who helped him regain the X Division Championship in a Falls Count Anywhere match.

[47] Lee and former Helms Dynasty teammate Andrew Everett lost to Dutt, Williams and Matt Sydal on the October 5 episode of Impact!.

[48] At Bound for Glory on November 5, he retained the title against Dutt, Williams, Sydal, Garza Jr. and Dezmond Xavier in a six-way match.

Lee was written off television in an angle where Killer Kross punched a concrete block through his face, which aired on the January 3, 2019 episode of Impact.

[66] Over the next few weeks, Grimes developed a winning streak, defeating Raul Mendoza and Boa before losing to Matt Riddle on the October 23 episode of NXT.

[88][89] On the November 11 episode of NXT, Grimes interfered in Lumis's match against Timothy Thatcher, subsequently wrapping his head in a burlap sack and attacking him.

[90] A blindfold match between the two on the following episode of NXT ended in an apparent no contest after Grimes unknowingly knocked the referee unconscious and ran off.

[98] On the April 27 episode of NXT, Grimes began a feud with WWE Hall of Famer Ted DiBiase after encountering him in a jewelry store over their watches.

[103] On the June 8 episode of NXT, DiBiase reintroduced the Million Dollar Championship and announced that the winner of a ladder match between Grimes and Knight at TakeOver: In Your House would win the title.

[124] On April 2, at NXT Stand & Deliver, Grimes defeated Hayes, Santos Escobar, Solo Sikoa and Grayson Waller in a fatal five-way ladder match to win the North American Championship.

[126] On May 3, Grimes would make another successful title defense in a triple threat match at NXT Spring Breakin' against Hayes and Sikoa.

[135] On November 8, Grimes lost to Gacy in his final match for NXT after interference from Schism's newest member, Ava Raine.

[138] On the July 21 episode of SmackDown, Grimes competed in a United States Title Invitational fatal four-way match, which was won by Rey Mysterio.