Reed attended Los Osos High School in Rancho Cucamonga, California, and San Diego State University.

The Chicago White Sox selected Reed in the third round of the 2010 Major League Baseball draft.

[4] Reed picked up his first career save on May 5, 2012, against the Detroit Tigers pitching one-third of an inning, striking out the only batter he faced, Austin Jackson, during a 3-2 White Sox victory.

On December 16, 2013, the White Sox traded Reed to the Arizona Diamondbacks for infielder Matt Davidson.

[11] On August 30, 2015, the Diamondbacks traded Reed to the New York Mets for Matt Koch and Miller Diaz.

Reed finished the 2015 season with a record of 3-3, 3.38 ERA, 4 saves with 51 Ks and a WHIP of 1.38 in 56 innings pitched in 55 games with both the Diamondbacks and the Mets.

On July 31, 2017, the Mets traded Reed to the Boston Red Sox for three minor league pitchers, Jamie Callahan, Stephen Nogosek, and Gerson Bautista.