As seen in Rudy's dream sequence in Totally Teen Genie, Sammy is a successful band manager, having won 157 awards in a single night with his girls. He is somewhat cocky and arrogant and uses "leet" speak when talking.
He also seems to be resilient to pressure, where in the episode "Totally Teen Genie", he accidentally wishes for Morgan and Macy to be the biggest things on the planet, causing them to grow into giants. He tries talking to them, but ends up being squashed under Morgan's foot as she steps on him.
In Starr Power, Sammy keeps asking HJ5 to sign on with his agency, but they keep rejecting him out of loyalty to Rudie.
Rudie encourages the band to accept the deal offered, because signing with Sammy is the best thing for their careers.
Sammy invites the band to headline for the Tanaka Boys in a packed stadium and offers the contract for G to sign.
After G hands it back to him, he discovers that HJ5 didn't actually sign it, it's covered in monster pet pawprints and they leave to go back to Rudie.
Sammy Starr next appears in Planet of the Rudies, where he reprogramms the tour bus' navigation system to travel to his holographic simulation environment, which has been filled with Rudie clones.
The idea was to get Rudie so distracted by his "virtual fans" that he'd be able to sign HJ5 to his talent agency.
Since most of HJ5 reject his request repeatedly, he tries to get Music to sign the contract on their behalf, but she tears up the contract, takes control of his limo and takes it back to the simulation to rescue Rudie and the rest of the band.