Betances was born in the Washington Heights neighborhood in Manhattan, New York and grew up in Manhattan’s Lower East Side. He pitched 8 of his 10 MLB seasons for the Yankees. During his tenure in the Bronx, Betances finished third in American League Rookie of the Year voting in 2014 and was named to the American League All-Star team for four consecutive seasons, from 2014 to 2017.

During those four seasons, Betances posted a 2.11 ERA and 14.4 strikeouts per nine innings in addition to 17 wins and 32 saves. In 2014 and 2015 in particular, he pitched to a 1.40 and 1.50 ERA, respectively. In 2018, he became the first reliever in MLB history with five straight seasons of 100 or more strikeouts. He made three postseason appearances with the Yankees (2015, 2017 and 2018).

Among Yankee relievers, Dellin ranks 6th all-time in appearances, 13th in saves and 3rd in strikeouts behind David Robertson and Mariano Rivera.

Betances pitched for New York Mets in 2020 and 2021, appearing in 15 games in 2020 and one game in 2021.

Coming out of Progress High School within the Grand Street High School in Brooklyn, Betances was rated as a top pitching prospect after being named an All-American in 2005 and a member of the Team USA Junior National Team. In 2006, he was drafted in the eighth round of the MLB Draft by the Yankees. He made his Major League debut on September 22, 2011 with the Yankees.