We know from the expensive tombstones that many successful gladiators went on to happy and successful retirements as freedmen. Generally speaking, they probably received their freedom upon retirement (or even before - there are indications that some freed gladiators stayed in the arena). Some of the most popular career choices were probably staying in the business by training new gladiators or becoming referees in the games.

It is interesting that, generally, gladiators were of a disreputable social class. Yet retired ones could enjoy some social mobility and join the local ruling class. The emperor Septimius Severus received an embassy of ambassadors which included an ex-gladiator, but it was considered unseemly for him to receive such a person and the embassy failed. We also have an inscription which shows an ex-gladiator received citizenship in several Greek cities and was a member of a prominent association in Rome.

Their notoriety may have excluded them from associating with the highest elites, but they could have respected positions in their local communities.

Source: M. J. Carter; Gladiatorial Combat: The Rules of Engagement