If you served prison time of one year or more, there is something called WOTC - WOrk Opportunity Tax Credit. Google search it. It provides an employer up to $2,400. off the top of their taxes to hire an ex felon. Sometimes money talks.
Another thing to do is to write on the application "will explain". If the employer is curious enough, you will get an interview. Focus on what you have done since your convction to right the wrong. "I do have a felony conviction for drug posession and I served my time which taught me many things like a trade or interpersonal skills and from what I have learned, I know that I would be a good employee with your company." If you are still on probation, you have an officer who is assuring you through UDS.
Depending on what State you reside, you may also qualify for State Vocational Rehabilitation services. Many of them (sorry, may not be all) work with individuals in recovery to help them find employment. Often time they will offer OJT (On the Job Training) and pay up to 50% of the wages for a short period of time as a try out.
Also, some states, but not all states, have a Federal Bonding Program through US DOL.
For all indiviudals, I can say that it is often true that "Having a job helps you get a job" meaning taking any job could be a step on the ladder.
What kind of work are you seeking? I will say that honesty is the best policy as HR people do speak with each other so do not ruin your credibility by lying on an application or in an interview. Admit and then quickly turn to what you have learned and how it can be an asset.
Also, small employers are easiest. They can often flex on their hiring policies. Corporations cannot. List what you have got going for you and explore how to sell your assests and not your liability.
