Brek Bannin grew up on the planet Tharr which is considered one of the hottest inhabited planets in the galaxy. Brek's family live in the hottest valley of the planet where the inhabitants developed the power to create super cold, snow and ice as a way to combat the persistent heat.

He first tried out for the Legion in Adventure Comics #306 but was unable to control his powers. He was rejected because members felt his powers might interfere in missions. Bannin then started the Legion of Substitute Heroes with other rejected applicants, and was their first leader.

He was the youngest person to ever try out for the Legion. He and the Subs aided the Legion numerous times mostly as local law enforcement while the Legion was off-world. Later he disbanded the Subs and joined the regular Legion, eventually becoming their leader and staying with them until they disbanded.

Polar Boy was often characterized as well-meaning but overeager by Legion writers. He was almost always illustrated as being considerably shorter than the other Legionnaires.

Following the Zero Hour reboot, Polar Boy was reintroduced in Legionnaires #43 (Dec 1996), in which he was once more rejected for unstable powers, and formed the Substitute Legion. It was mentioned that this incarnation was not younger than the other Legion candidates, but was assumed to be such due to his height.

Polar Boy appears in the Threeboot Legion as a member of the Wanderers. His powers are described as slowing molecular movement.

In an alternate timeline noted by Waverider, the original Polar Boy successfully recruits the time-lost Justice League hero Blue Jay.

In Action Comics #860, Polar Boy is seen in a torture camp, captured by the anti-alien society of 31st century Earth. His arm had been ripped off, but upon his release by Superman and the Legion, he created a replacement out of ice.