The first Saiyan to achieve the level of Super Saiyan 2 was Gohan. This transformation occurred during the intense battle against Cell in the Cell Games. Gohan’s transformation was triggered by his deep emotional response to seeing his friends in danger and the motivational words from Android 16.
This powerful moment allowed Gohan to tap into a new level of strength, surpassing the regular Super Saiyan form and becoming the first to reach Super Saiyan 2. This transformation significantly increased his power, speed, and energy output, making him a formidable force against Cell.