Englishman:
A Felony conviction remains on a persons record. There are some States that allow a Felony conviction to be expunged after 10 years. It is not automatic the Felon must ask that it be taken off.
Talesin:
The United States prison system is more then half full of non violent drug offenders. Changing the law on marijuana alone would halve the prison population and free up the courts and police to pursue robbers, rapists and murderers.