I found two sentences in the Oxford dictionary.
1. It is importedfor him to attend every day.
2. It’s important to me that you should be there.
(I am highlighting the way it is done in the dictionary.)
What’s the difference between important to and important for? Maybe it is connected to the construction following it?
“important to X” means that X thinks it’s important.
“important for X” can mean the same, but can also mean that someone else thinks it’s important, or that it’s important according to some objective criteria. The latter meanings are often expressed in the form "important for X to ", as in your example.