A Green Lantern is not an island unto himself. Similarly, neither was much for taking a backseat to others, given the nature of being selected with the power battery and all.
Hence, shortly after assuming his heroic alias, Hal Jordan encountered the Green Lantern Corps and then was a charter member of the Justice League of America. With the former, he quickly became noted as the most intuitive, possessing innate leadership qualities in the Corps. From time to time, he was also a chairman of the JLA, although this was a more rotating position. Then, during a confrontation with Krona that threatened the cosmos, it was Jordan who led his fellow Green Lanterns to victory despite immeasurable odds.
Previously, Alan Scott had decades earlier joined the Justice Society of America during its initial case, and after teammate Flash left the team he as the Green Lantern became the teams second chairman. Shortly thereafter, while battling the evil Wotan, Lantern failed to save a small boy which led to Scott leaving the team for a time. Soon he joined the All-Star Squadron, although only as an on-again off-again member, never leading that team into battle. However, he was an example to be imitated by later generations, including his children Jade and Obsidian.