What is the definition of a Johnson Waiver? And how is it used?

A Johnson waiver means that a Defendant gives up or waives part or all of his back credits on a case for the purposes of sentencing. Why would a Defendant do that? To avoid prison on a probation violation, as part of a deal to strike a strike or other reason. If he is not getting anything out of it then he may not wish to do it - consult with the current attorney to make sure everybody understands what is involved. www.losangelesdefenders.com

Because you can't serve more than a year in the county jail if you are granted probation. Therefore, you would need to agree that in a situation, such as a probation violation where you have maxed out your county jail time, that you agree to serve more than the year in the county jail instead of going to state prison. This may involve giving up custody or good time/work time credits.

Questions in the opening, given the balance of the post, are a bit confusing. The other responders are correct in the definition and use as to a Johnson Waiver. The only application that seems to make sense here is that the person of whom you speak has served a year in county jail. The DA is seeking to send the probationer to prison and judge is willing to give one more chance. Therefore, probationer has to give up the credits earned for additional time in county jail but judge is sentencing him/her to prison but staying execution of the sentence. This arrangement is what is commonly called a "joint suspension". I reguarly practice in the Stockton courts. From experience, I can tell you that, if my guess about the circumstances is correct, this is an absolute last chance.