Liam Brennan was a Human child in the fourth grade in the year 2151. A student in Miss Malvin's class at the Worley Elementary School in Kenmare, County Kerry, Ireland on Earth, Liam was among the students who sent questions, letters, and drawings to Enterprise NX-01.

Liam's question was "What do you eat?" and one of the few that Captain Archer personally answered. Archer detailed the methods of procuring and preparing food using peanut butter and jelly sandwiches and turkey, with all the trimmings, as references as to the versatility of food choices aboard the Enterprise. (ENT: "Breaking the Ice")

This character was only mentioned in dialogue.
In the script of "Breaking the Ice", this child's name was given as "Robin Moore".