Strong Guy & Wolfsbane

After the Shadow King was defeated, several of the Muir Island mutants, with the help of Valerie Cooper, were recruited into the new X-Factor team. His teammates included the former X-Men Havok and Polaris, as well as Wolfsbane and Quicksilver. At this time, Guido picked up the codename "Strong Guy" as a joke at an X-Factor press conference.

One of the first villains the team faced was Mister Sinister and his lackeys, the 'Nasty Boys'. Sinister wished to discredit mutantkind and used X-Factor to do so. One of Sinister's behind-the-scenes allies was a power-hungry Senator with the power to cause bad luck, who manipulated Strong Guy into destroying the Washington Monument while fighting Slab, one of the Nasty Boys. The Senator, who was after the entirety of the X-Factor team, was later slain by Mr. Sinister himself.

During his time on the team, he had a blossoming romantic relationship with a powerful Genoshan mutant and political dissident named Jo Beth. He even visited her Grandmother at her calm, suburban home on the island of Genosha. She took a shine to him instantly.