McNamara is also known for successfully negotiating a monstrous barrel at Jaws and being the first person to ride a wave formed from calving glaciers.

In Berkeley, McNamara, and his younger brother Liam, were both known by friends to be rather fearless and to shrug off the pains of rough childhood play, foreshadowing his later ability to face danger while surfing.

[2] At 11 years old, McNamara followed his younger brother's footsteps and began surfing at Sunset, Waimea and the outer reefs in search of giant swells.

After training for a year, McNamara and tow-in partner Rodrigo Resende won the $70,000 purse at the Tow Surfing World Cup in Maui at Jaws in 2002.

[3] Later that year, he posed for the cover of major surf magazines around the world after being photographed in a dramatic barrel shot off of the coast of Teahupo'o in Tahiti.

The boundaries of big-wave surfing were pushed once again in the summer of 2007 by McNamara and partner Keali’i Mamala, seeking tsunami formed by 300-foot (91 m) calving glaciers in South-Central Alaska.

Rescuers on jet skis eventually pulled McNamara to safety, and he suffered a dislocated shoulder and a broken upper arm that required surgery.

[10] McNamara became interested in Stand Up Paddle (SUP) and gave it his own twist by designing and creating SUP boards for a more extreme experience, venturing into big wave venues like Waimea, Puerto Escondido, and Mavericks.