Sam was brainwashed and planted for Captain America to find and befriend by the Red Skull. After that, he took the name Falcon and spent his time between the cleaning up the streets of Harlem and playing attache to Captain America. Through the relationship with Captain America, he went on to playing a bigger role in the heroic community including joining America's premier superteam, the Avengers, and working with S.H.I.E.L.D. on many occasions. Because he was brainwashed into becoming a good guy, the memories of his former life have come to the surface more than once but he remains a hero in good standing.
His abilities are that of an highly trained, gymnastic athlete with two exceptions. He has the ability to mentally communicate with birds, a bond that is strongest with his bird companion Redwing. He also has a complicated retractable flying apparatus that provides him with a variety of aerial combat capabilities besides just flying. The latest set was provided by fellow hero and benefactor, the Black Panther.
This character has little obvious impact on the Marvel Comicbook Universe but he has been around since late 1969. He is trustyworthy, caring, and quite heroic but ultimately uninteresting. His abilities are limited but I guess flight added to the ability to kick ass is enough. Considering the era this character was introduced credit does have to be given to the fact that he has stood the test of time. There are action figures of his likeness out there and he even made it to the Marvel animated universe during the short-lived Avengers: United They Stand animated series. Here's a look: