Cyclops was the first mutant to be taken in by Charles Xavier. His training under Xavier and leadership skills made him an obvious choice for the leadership position of Xavier's X-Men team.
When the Leader stole Professor Xavier's mutant-finding machine known as Cerebro, Xavier dispatched the X-Men to get it back. Despite the fact that the Leader was mind-controlling the Sentry and using him to fight the X-Men, Cyclops and his fellow X-Men were able to defeat the Leader, thanks primarily due to the combined telepathic efforts of Professor X and Jean Grey used on the Leader. They then discovered that the Leader was keeping Cerebro somewhere in Europe, but before they could get to it the Latverian monarch Dr. Doom ordered an airstrike on the location in order to destroy Cerebro. The X-Men believed Cerebro to have been destroyed, but they soon found out that it had somehow survived the bombing. As it would turn out, the mysterious Fantomex snatched Cerebro right as Doom's aircraft were bombing the building.
Realizing that Cerebro was in the hands of some organization in Europe, Cyclops and the X-Men travelled to Austria where the Latverian airstrike had occured and tried to track Cerebro from there. They were found by a group of militant European mutants (who had found them easily usign Cerebro) who sought to bring forth a peaceful community of coexistence of mutants and humans by any means necessary (even terrorism and violence). Thanks to the help of the Russian mutant Colossus, who was part of the terrorist group but was uncomfortable with their violent ways, the X-Men were able to defeat that small squad of mutants. Cyclops then came up with the plan to feint being members of the terrorist organization in order to get into their underground base in the sewers, which Colossus led them to; however, Cyclops' plan was revealed by the leader of the organization, Fantomex, who was somehow able to read from the X-Men's body language and facial expressions that they were deceiving him. In the ensuing battle, Fantomex escaped the sewer and set off explosives to collapse the entire place on both the X-Men and his own mutant followers. The X-Men were able to escape with Cerebro and even rescued some of the European mutants.
Cyclops was present for both of the X-Men's battles against Terrax; however, his optic beams proved to be not nearly enough to defeat the powerful being.