Here's the list of TSA disqualifiers:

Background Check Info

These are federal rules, and are not waiverable. Theft counts, but only if it's a felony. After ten years, it will no longer be disqualifying.

These rules apply to all airport employees with access to flight ops areas, including pilots.

However...IMO airlines are pretty much not going to hire a pilot who has a theft conviction after age 18. The only chance I would see would be after at LEAST 15 years with a squeeky-clean record.

Even if you get it expunged, there's no guarantee that the airlines won't see it in the FBI database.

I would not invest time and money pursuing an airline career with that on your record. You could go after part 91/135 corporate or charter flying although some operators will not be able to hire you for ten years due to the TSA requirement (depends on what airports they serve). Some 91/135 operators (the best ones) will probably not like the heft conviction but you could probably find a job somewhere.