His mutant powers were triggered in childhood during a battle with schoolyard bullies, causing him to become overly muscular and isolate further from his peers.

Guido coped with his pain by developing an outgoing "public face", rarely letting even those close to him see him in discomfort.

[4][5][6] He later works with several Muir Island mutants to defeat the Shadow King, after which they form a new incarnation of X-Factor.

[10] With X-Factor, he aids the American-supported Trans-Sabal government in a war against rebels, and fights the Hulk,[11] then battles the Mutant Liberation Front.

[15][16] In The Infinity War, Strong Guy is among the superheroes who travel across the multiverse to battle Adam Warlock's alter-egos, the Magus and the Goddess.

[20] His other best friend on the team, Multiple Man, is seemingly killed attempting to remove the Legacy Virus from his body.

However, he no longer has a soul, which leads him to become more aggressive and eventually kill Wolfsbane's son Tier to become the Supreme Hell Lord.

[37] In Secret Empire, Strong Guy is seen among the inhabitants of the mutant nation of New Tian following Hydra's takeover of the United States.

Strong Guy's powers first appeared after being beaten by bullies and hit by a bus; unable to expel the energy, his body was permanently warped.

[3] Strong Guy's maximum strength level is such that he has sufficient power to move the Blob,[42] or briefly stand toe to toe with the Hulk, although the latter's rage-enhanced strength was so powerful that the energy of channeling merely one blow put Strong Guy in danger of a heart attack afterwards.

[volume & issue needed] An alternate universe variant of Strong Guy from Earth-295 appears in Age of Apocalypse.