The people who work in the legal system get held to a relatively high standard when it comes to how their personal interests affect their job. Neither a judge nor an attorney should play a role in a criminal case where they have either personal experience that would contribute to bias or some kind of conflict of interest.
For example, a judge likely should not oversee criminal proceedings against the owner of a business if their child is one of that business’s competitors. Your lawyer has a fiduciary duty to act in your best interests, but if they or someone they know might benefit or profit from you losing your criminal case, that could lead to them not providing you with the standard of representation that you deserve.
If you can establish a conflict of interest in someone who played a role in your court case that resulted in a conviction, such a conflict of interest might justify an appeal.
Generally speaking, in order to appeal, you must show unfair circumstances
Those facing criminal charges have many protections and rights under federal and state law. If a defendant believes that the courts somehow violated their rights, either through the use of illegally gathered evidence or the assignment of a sentence that does not align with state law, it may be possible for them to appeal either the conviction or the sentence they received.
However, in circumstances where a defendant is simply frustrated with their conviction or thinks the court ruled improperly, they won’t generally have grounds for an appeal. If you have documentation or witness testimony related to a potential conflict of interest that influenced your attorney, the prosecutor or the judge, that they give you grounds for an appeal.
Sometimes, jurors can also have a conflict of interest
The process of jury selection is lengthy and in-depth in order to ensure a relatively neutral pool of jurors who have no personal interest in the case or history with similar criminal offenses in the past. Biased jurors absolutely affect how fair your trial will be.
If information comes out that shows that there was an undisclosed or intentionally misrepresented conflict of interest that influenced one of the jurors, that could also be grounds for an appeal. Examples could include a juror in an impaired driving case not disclosing that their high school sweetheart died in the drunk driving crash. Additionally, someone who stands to benefit financially or professionally from a conviction would also have a conflict of interest.