I agree with the other posters above - graduation is just a ceremony. Once you have completed the requirements of high school, you have earned the diploma. However you should certainly check in with the office or guidance staff about what will be sent to colleges and when. Your diploma does not get sent to colleges, it gets handed or mailed to you (and you should get it and hang onto it, you may need it in the future). What high schools do send to colleges is a transcript, which is a copy of the final record of your classes, grades, and disciplinary items. Generally speaking, transcripts are not mailed automatically; you have to make a written request to get them sent to a college. If a college does not get a copy of your final transcript, that could indeed create problems. It's the students responsibility to check and make sure that that gets sent.

Graduation is a ceremony, not a requirement.  Though parents and friends usually want you to participate, not doing so doesn't have any adverse on your record at the school, as it shouldn't.  Another way people look at it is that school is a requirement, graduation is a privilege you earn, and we don't have to exercise our privileges.

For many graduates, that opportunity to walk across the stage and collect the folder into which the diploma will later be inserted (after you've returned all library books, finished paying fees, whatever other remaining hoops you need to jump) is a moment of affirmation that you have completed all the hard work involved in achieving the status of graduate!

For others, the ritual and display is meaningless (I know I've done it and I don't care if anyone else knows) or a waste of time. Either way, actual attendance is not related to actual graduation. Congratulations!

If you have fulfilled your obligations for graduation, then you have graduated, as far as colleges are concerned. In fact, at many colleges, many students do not show up for graduation in my experience. As pohnpei said, the only way it might have a bearing on college would be if you committed some honor violation or felony that resulted in long-term suspension--something that might affect your admission, which is not irrevocable. All this being said, if I had missed graduation, I would have had to answer for it to my family, which would have been worse than any academic consequences.

In my experience the above posts are all right. Your graduation is not dependent on attending the graduation ceremony. The graduation ceremony is just that, a ceremony formalizing and celebrating a significant achievement. 

Congrats to you on finishing high school if you are this hypothetical student. 

Attending graduation is not a prerequisite for graduation. Typically, the school will hold onto your diploma or it will be mailed to you later. The schools I have worked for mail diplomas. As stated in post #4, graduates receive stock diplomas, not the real one. This is the same for colleges and universities.

does his diploma still get sent to universities and colleges if a student misses the graduation ceremony?

If a high school student has all the required credits and is ready to graduate but misses graduation night, does his diploma still get sent to universities and colleges? 

You definitely still graduate! I promise. Most schools don't even hand real diplomas to you at the ceremony, you have to run in and pick them up later on. Don't worry about missing the ceremony. Let someone know, but fear not!

No, missing graduation has no impact.  The only problem would be if you missed for some disciplinary reason.  If you did that, it would be possible that a college would care.  But the college is not informed whether you actually attended your graduation.  All they care about is that you fulfilled the requirements and are officially a graduate.  

The best thing to do would be to check with your school.  I wouldn't think that missing the ceremony in high school could prevent you from receiving your diploma, but considering all the work you've done to earn that piece of paper... I wouldn't want to take any chances.