Gallagher was almost forgotten about because of the crowded blueline that the U.S. national U18 program had, but he stands out in his own right. He displays strong edge work and has an efficient first three steps, generating speed and acceleration through the neutral zone when given space. He has the mobility to keep a solid gap with his opponents and is never far away from the play. On the power play he likes to use his shot, often setting himself up in a great position for a one-timer. He has good power and control in his one-timer and is able to hit the net on the majority of his shots. His wrist shot is also powerful, but he could improve his release. He is able to control the puck well, especially along the boards. He is active with his stick, able to make plays defensively by breaking up passes, forcing turnovers and taking away space. In tight areas he displays strong puck control and is able to use he skates to make a play. Reads the play well and makes smart plays in all zones, rarely taking high risks. When under pressure in the defensive zone he is creative, being deceptive with head and shoulder fakes to gain more space and time, and he uses the boards to make passes around opponents to his teammates. He displays great anticipation, being able to  read the play and get into perfect positioning to get to the puck first. Shows hunger for the puck and has great bursts of energy, often out-working opponents. When he finds himself out of position he displays great determination and is able to get back to help defend. In straight-line situations he tends to pitchfork and swing his arms side to side, rather than extending in a forward and backward direction. This also leads to him not always having his stick on the ice going into battles, or in key defensive situations. A steady and sturdy defender overall, if not exactly an exciting one.

– FCHockey’s 2021 NHL Draft Guide