How does an E6 have 6 service stripes?

Can't tell his branch, but looks like he also has seven combat zone stripes.

The new RCP for staff sergeants is 20 years of service. Since 2008, they have been allowed 23 years. There are 3 possible reasons I see: He is a Re-thread, he got out came back, busted, or in a very high density MOS SFC is way to hard to get to.mBut don't ever ass-u-me to know by a picture any persons history. His ribbons tell a different story of a soldier with awards that include a CAB and his combat bars by my tired eyes, are 8 and that means 4 years down range. That's a hard almost 1/4th of his career.!

I have seen an SP4 with 7 service stripes due to being busted. When I retired there was a SGT E-5 retiring and he had also 7 service stripes. Many soldiers retire as SSG and SFC and have 6 service stripes.

Some career fields have a vary narrow path to career advancement, with only so many slots for E-7, and even harder after that. There are a number of factors that contribute, as medical, I didn’t have the EFMB, and in 1994 I had a Senior 91P (68P) SGM inform me that I would not see E-7 without earning the EFMB. I had earned my Bachelors, but it didn’t help. I retired in 2008, I had positive experiences with every assignment, I’d still be serving if allowed. I had 7 service stripes when I retired.

I retired as an E-6, 13 years time in grade and proud of it. No article 15’s, I just didn’t kiss butt plus I ruffled a few feathers along the way. During my time, when it came to DA selection boards it all depended if someone knew you are not and if you kissed their butt or you pushed them off at some point. I am proud of my service and my accomplishments.

Many reasons. Broken service. Reduction and recovery. Just two of a few.

He was maybe an officer who resigned his commission and went back to his last enlisted rank to serve out the remainder of his enlistment. We had an E-6 who was a Captain but he didn't have a college education so he had to step down.

There could be several reasons why. One possible reason is the MOS the person is in could be a hard MOS for rank. Another reason could be the person may have been reduced in grade at some point or they may have gone from Reserve to active duty at some point

A break in service resulting in a reduction of ranking upon re-entry or changing branches of service might do it.

Is he active duty or is he in the National Guard?
If he's in the Guard, I can tell you that he's an E-6 with over 18 years because, unlike the active Army, he can only get promoted within his MOS and within his state.
So if he's a squad leader in an engineer company and there is only one engineer battalion in the state, that means 3 companies with 3 platoons of engineers (1 platoon in each unit is HQ platoon and one unit in the Battalion is the HQ company). In order for him to make E-7, he has to compete for exactly 9 Platoon Sgt slots in his state of which only 1 will open when someone either retires or is promoted. If the E-7's and E-8's are all young, he may never see another promotion.

Bottom line, once you hit E-4 in the Guard, promotions will slow down and after reaching E-5, they become almost stagnant.

As for myself, I retired at 21 years as an E-6.