Originally Posted by
Juanefny
For those of you who have a maternal name... if you would like to have it show up on your Globalentry card, then put the maternal name in the the last name area. So if my name is smith thompson, then put both of them under last name and if you would like, you can also put the thompson under maternal. Rather odd, but b/c mine was only put under maternal name, it didn't show up on my card

That's the way it usually works on USG-issued photo ID. The maternal name is mostly retained/used for background verification and other such purposes rather than inclusion on federal government-issued photo ID.