Mac started sailing in the Optimist when he was 5 years old during a summer at the Club Nautico Villa Constitucion in Argentina. He continued competing in Florida, representing Lauderdale Yacht Club, Miami Yacht Club, and the U.S. at many international events. He was also part of the 2005 Melges 24 World Championship winning team.
At the age of 14, Mac transitioned into skippering the 29er for his crew Ian Simms, with whom he was selected to be on the 2009 U.S. Sailing U18 Team, and later Timmy Zenderman, with whom he again was picked to be on the 2010 U.S. Sailing Development Team. In 2009, Mac got second at his first U.S. Youth Championship in the 29er, and went on to compete in the 2009 and 2010 29er worlds. In 2010, he was also selected to represent the U.S. at the ISAF Volvo Youth Worlds in the SL16 catamaran with skipper Taylor Palmer and brought home a bronze medal.
After the summer of 2010, Mac paired up with his longtime friend and rival, Antoine Screve, and again represented the U.S. at the ISAF Youth Worlds. They won the qualifiers and went on to win a Silver Medal at the 2011 ISAF Youth Worlds in Zadar, Croatia.
In 2012, he has been competing mostly in high school sailing and coaching the new 29er program at Coral Reef Yacht Club. Mac also sailed the Miami OCR in the 49er this year with Thomas Barrows and finished 13th after being exposed to the boat only a handful of times. In the fall of 2012, he looks forward to attending Boston College, where he will be part of the Varsity Sailing Team.