We can't agree about school or a doctor. Who decides?
Read the order first: joint legal custody means you must consult each other, and it usually does not say what happens when you cannot agree. That silence is the actual problem. Neither parent can lawfully act alone, and nothing in the document breaks the tie.
Which is why a school enrollment deadline turns into an emergency motion so often.
Establish what you actually have
Sole legal custody for one parent means that parent decides, after informing the other where the order requires it.
Joint legal custody means shared decision-making on major matters, typically schooling, non-emergency medical care, and religious upbringing. Day-to-day choices stay with whoever has the children at the time.
Split by category is increasingly common and worth knowing about: one parent decides education, the other decides healthcare, or one has final say after genuine consultation. If your order does this, your answer is already written.
Legal and physical custody are separate questions, and a parent with less time can still hold equal decision-making authority.
What not to do
Do not enroll or switch unilaterally where you share legal custody. Courts take this seriously, it can be reversed, and it damages your credibility on everything else in the case. A parent who moved a child to a new school without consent starts every subsequent hearing explaining that.
Do not use the child as the messenger, or ask them to state a preference to break the tie. It puts them in the middle of a decision that is not theirs, which is the one thing that does lasting harm regardless of how the schedule ends up.
What to do instead
Ask in writing, with a deadline. "The application is due on the 14th. Here is what I propose and why. Please let me know by the 10th." This resolves more disputes than anything else, and if it does not, it becomes the record showing you tried.
Propose a specific alternative rather than restating your position. Deadlocks often break when someone offers a third option.
Mediation, for the single issue. Far cheaper and faster than a motion, and many courts expect you to have tried.
A parenting coordinator, where your area has them: a neutral professional who works through exactly this kind of recurring deadlock without a hearing each time. Appointment usually needs both of you to agree or a court order, and whether their decisions actually bind you varies by state, so ask what authority yours would have.
A motion for decision-making authority on that issue. Courts can grant one parent final say on a specific subject without changing anything else. That is often the right ask, and a narrower one than it sounds.
Getting the records
A separate question people conflate with this one, and the answer is usually better than they expect.
Under FERPA, a public school, or any other school that takes federal education funding, generally must give both parents access to their child's education records, including a non-custodial parent, unless it has been given a court order, a state statute, or another legally binding document that specifically revokes those rights. You do not have to go through your co-parent. Ask the school directly, in writing, and give them a copy of your order if they ask.
Most private and religious schools do not take that funding and are not covered by FERPA at all. There, access comes from your order and from the school's own contract with you.
Those rights end sooner than parents expect. They belong to you only while your child is a minor in school. They transfer to your child at 18, or the moment they enroll anywhere after high school, whichever comes first. A college may still share records with a parent who claims the student as a dependent on their taxes, but it does not have to, and many will not. If you are the parent paying tuition under a decree, the reliable route is a signed release from your child, and nothing in the process will prompt you to ask for one.
Medical records work differently and depend on your order and your state, but joint legal custody commonly carries the right to obtain them and to be informed about appointments. If your ex will not tell you who the doctor is, ask the school, the insurer, or your attorney rather than fighting about it.
There is one exception that runs the other way, and it exists in every state regardless of what your order says. A provider may decide not to treat a parent as the child's representative, and so not release the records, where it reasonably believes the child has been subjected to abuse or neglect by that parent, or that giving that parent the records could endanger the child. If you are trying to keep a child's therapy records away from someone who hurt them, that is worth raising with the provider directly. It is also the explanation if records have already been withheld from you.
Fixing it properly
If this keeps happening, the plan is the problem. A tie-breaker, a category split, or a required process before either parent acts is exactly what a parenting plan should have contained, and adding one now is cheaper than litigating the next deadlock.
What "major decisions" covers, whether parenting coordinators are available, and how medical records access works all vary by state. FERPA governs school records at federally funded schools, and the details are worth confirming with a licensed family-law attorney if a school is refusing you.