Despite Cramer's assertion in his CNBC bio that he has "one of the best records in the [hedge-fund] business," I am aware of no independent analysis that has confirmed this. To confirm it, one would have to evaluate not only the performance of Cramer's hedge fund for the period in question (the late 1990s) but the performance of the overall markets during the same period (extraordinary). One would have to assess whether the fund was taking more or less risk than the market (more risk usually equals higher returns). Lastly, one would also have to understand exactly how much of the fund's performance Cramer was responsible for (he doesn't say that the fund had one of the best records in the business—he says that he does).
In short, it may well be that Cramer put up excellent numbers during his career as a hedge-fund manager. But we don't have enough information to confirm this.