If probation is granted to a defendant after a conviction you may be eligible to get your record cleared/expunged. In fact, you are eligible to get your record expunged whether you went to trial and lost or if you pleaded guilty and were placed on probation. Penal Code Section 1203 governs expungement, whether the district attorney or city attorney prosecuted your case.
Usually the probationer must complete their entire period of probation successfully to get an expungement. Even if you violated your probation, you are still eligible for an expungement. If expunged, the conviction is set aside and the case is dismissed from the defendant’s record. The defendant then has the legal right to say that he has not been convicted of any crime, even when applying for a job (subject to certain exceptions, such as applying for a job with the county, state, etc.).
If a defendant is sent to state prison, and thereafter paroled, the process is more complicated and generally requires the parolee to get a “certificate of rehabilitation”.
Expungement is a remedy available for most felonies and misdemeanors, although not all.