On January 13, 2012, Smith defeated The Almighty Sheik and Kevin Steen to become the first Heavyweight Champion of Resistance Pro Wrestling promotion. Over the next few months, Smith would take on Rhino in various matches culminating on May 11, in a steel cage match with special referee Raven which once again Smith would win. However, the title was stripped on October 14, 2012.
On August 13, 2012, New Japan Pro Wrestling announced that Smith would be returning to the promotion the following month as a member of Minoru Suzuki's Suzuki-gun stable, forming a regular tag team with stablemate Lance Archer. Smith said that New Japan wanted a huge monster as Archer's partner. Also, he received a good offer from All Japan Pro Wrestling, but he chose NJPW due to the previous relationship. Smith wrestled his return match on September 7, when he, Lance Archer, Minoru Suzuki and Taka Michinoku were defeated in an eight-man tag team match by Hiroyoshi Tenzan, Satoshi Kojima, Togi Makabe and Yuji Nagata, following a disqualification. On September 9, Smith submitted IWGP Tag Team Champion Hiroyoshi Tenzan in another eight man tag team match, after which he and Archer, dubbing themselves K.E.S. (Killer Elite Squad), made a challenge for his and Satoshi Kojima's title. On September 24, New Japan renamed Smith "Davey Boy Smith Jr.". On October 8 at King of Pro-Wrestling, K.E.S. defeated Kojima and Tenzan to win the IWGP Tag Team Championship. K.E.S. made their first successful title defense on November 11 at Power Struggle, defeating Tenzan and Kojima in a rematch. From November 20 to December 1, K.E.S. took part in the round-robin portion of the 2012 World Tag League, finishing with a record of four wins and two losses, advancing to the semifinals of the tournament in the second place in their group. On December 2, K.E.S. defeated Always Hypers (Togi Makabe and Wataru Inoue) to advance to the finals of the tournament. Later that same day, K.E.S. was defeated in the finals of the 2012 World Tag League by Sword & Guns (Hirooki Goto and Karl Anderson). On January 4, 2013, at Wrestle Kingdom 7 in Tokyo Dome, K.E.S. defeated Sword & Guns in a rematch to retain the IWGP Tag Team Championship. On February 10 at The New Beginning, Smith and Archer defeated Tenzan and Kojima for their third successful defense of the IWGP Tag Team Championship. On March 11, Smith entered the 2013 New Japan Cup, defeating IWGP Intercontinental Champion Shinsuke Nakamura in his first round match. Smith's main event win over the former three-time IWGP Heavyweight Champion was referred to as the biggest of his career. Six days later, Smith advanced to the semifinals of the tournament with a win over Yujiro Takahashi. On March 23, Smith was eliminated from the tournament in the semifinals by Hirooki Goto. On April 5, Smith and Archer made their fourth successful defense of the IWGP Tag Team Championship against Shinsuke Nakamura and Tomohiro Ishii. Two days later at Invasion Attack, Smith unsuccessfully challenged Nakamura for the IWGP Intercontinental Championship. On April 20, Smith and Archer defeated Ryan Genesis and Scot Summers in Houston, Texas to not only retain the IWGP Tag Team Championship, but to also win the NWA World Tag Team Championship. On May 3 at Wrestling Dontaku 2013, K.E.S. lost the IWGP Tag Team Championship back to Tencozy in a four-way match, which also included Takashi Iizuka and Toru Yano, and Manabu Nakanishi and Strong Man, though neither Smith nor Archer was involved in the finish. K.E.S. received a rematch for the title on June 22 at Dominion 6.22 in a three-way match, which also included Iizuka and Yano, but were unable to regain the title, when Kojima pinned Archer for the win. On August 1, Smith entered the 2013 G1 Climax. The tournament concluded on August 11 with a match, where Smith was defeated by his tag team partner Lance Archer, costing him a spot in the finals and ending his tournament with a record of five wins and four losses.