Will Invisalign Fix an Overjet on a 35 Year Old Male?

Yes. Invisalign will fix an overjet
regardless of age of the patient if the aligners are worn as recommended and
with proper treatment planning by an orthodontist.

Yes, of course it will help. Will it totally remove your overjet? Probably not. But any improvement will aid in lengthening the life span of your teeth. Make sure to go to a preferred provider though.
Dr Thomas

Yes, absolutely you are a great candidate for Invisalign.
Crossbite and overjet can cause (jaw and bite) problems in the future so it is very good that are interesting in correcting these immportant issues. The nice thing is that no one will even know that you are in braces because they are clear and very easy to use. I strongly recommend that you stay with the treatment plan that your dentists recommends. Consider wearing elastics, it may shorten your treatment time. Wear your aligners day and night only to take them out when you eat or drink so that you will have good results at the completion of your Invisalign treatment.

Your description of your bite includes a cross bite and an overjet -- I'm assuming you mean that your upper teeth protrude out over your lower teeth by 6mm...if that is the case, Invisalign will be a good option for correcting this as well as your cross bite. Since you're already prepared to wear the trays all of the time (except when brushing and eating, well, I'd say you're all set. Good luck!!

Invisalign can improve an overjet of 6mm, but it may not correct the entire overjet. It is possible that elastics or other treatment adjuncts may be needed to fully correct the overjet but it is hard to say without seeing your mouth or records. I would recommend seeing an orthodontist who can analyze your teeth and bite and give you a range of treatment options to fix your large overjet of 6mm and crossbite.

Overjet correction with Invisalign can work great under two important conditions. First, significant spacing of the upper front teeth allows for overjet reduction as spaces are closed. Secondly, absence of a deep bite. In other words, if your front teeth overlap vertically so much that you can't see much of your lower front teeth when you bite together and the edges lower front teeth contact the back of teh upper front teeth near the gumline when biting, then you may have difficulty getting the overjet reduced without addressing other bite issues, possibly beyond the scope of predictable Invisalign treatment. Crossbite is a separate issue.
If these conditions do not exist, this is a much more complex case. A consultation with an orthodontic specialist will help you sort out your options and predictability of outcome with each.