Klein acquired a reputation as a tough negotiator who could bring money to his clients. Two of them, rockabilly singers Knox and Bowen, were owed royalties by Roulette Records. Morris Levy, co-owner of Roulette, was feared because of his organized crime connections. He was known to pay artists as little as possible. Klein persuaded him to pay Knox and Bowen the royalties they were owed over a four-year period. Klein's success with the Knox and Bowen negotiation brought him new clients, and he and Levy became lifelong friends.