Mas is the Chairman of the Board and Co-Founder of MasTec, which according to its web site, is "a part of some of the largest and most complex infrastructure construction across the country."　

Mas also is Chairman of the Board of the Cuban American National Foundation, an organization founded in 1981 dedicated to the promotion of a free and democratic Cuba.

Beyond serving as chairman of MasTac and CANF, Mas is the managing partner of a private equity group with investments in the fields of aviation, banking, commercial real estate, healthcare, and fixed income trading market makers.

Mas also serves on the Board of Overseers of the University of Miami School of Business