Hi Wylie,
You will want to include your one-year old in your party size when making
Advanced Dining Reservations. This will ensure that the table reserved for your party will be large enough to accommodate everyone in your family - whether they use a regular chair, wheelchair, highchair, or infant carrier. Once you arrive at the podium to check-in for your reservation, simply inform the host or hostess that you need a highchair for your little one. They will prepare your table accordingly.
As a side note, I want to take a moment to make sure that you are aware of the
Baby Care Centers which are available for your convenience in each of the theme parks. I have included a video for you with more information. I believe that you will be happy to discover this wonderful, complimentary perk for parents of infants and toddlers.
Thank you for visiting the Disney Parks Moms Panel!
Wishing you magical memories,
Kaylene