In 2013, Martinez became the first Cuban-American to serve as a chief of staff in the U.S. Senate, and has been a long-serving adviser to Rubio. Prior to being chief of staff, he served as deputy chief of staff in the Senate office and was a senior advisor to Rubio’s Reclaim America PAC and the 2012 Romney for President campaign. Previously, Martinez served as communications director for the Republican majority during Rubio's term as speaker of the Florida House. In 2009, he stepped down as chief of staff to the majority whip in the Florida House to work as a senior adviser to Rubio’s 2010 Senate campaign. Prior to his work with Rubio, Martinez served as deputy speechwriter for Governor Jeb Bush and Florida communications director for President George W. Bush’s reelection campaign in 2004.