Captain Michael Sarlo, who is also the department's executive officer, will take over the post when Ecker retires on Dec. 28.
The town board approved his appointment 5-0. His salary will be negotiated later.
Sarlo, 43, joined the department 19 years ago this month, and quickly rose through the ranks.
"I am extremely honored to be chosen as our community's next chief of police. I would like to thank Supervisor Wilkinson and the town board for selecting me," Sarlo said. "I am extremely proud of the dedicated and professional men and women of the EHTPD. I look forward to continuing to serve the citizens of East Hampton."
By phone, Ecker said he was pleased with the town board's decision. "I'm very, very happy for Mike and his family," he said. "I know the police department will be in good hands and I look forward to a nice transitional period."
Sarlo grew up in East Hampton. His parents, Chris and Pat Sarlo moved to East Hampton in 1975. His father was a principal at East Hampton High School for 19 years.
Sarlo graduated from East Hampton High School in 1988, and went onto earn his Bachelor's of Arts in speech communication from University of Maryland, College Park.
The town hired him in 1996, and he worked in the patrol division through 2001, mostly in Montauk. In 2002, he was promoted to sergeant, and he made lieutenant just three years later. He was promoted to captain in January 2009, and later the executive officer when Ecker became chief in 2010.
Sarlo has served as the Montauk and East Hampton precinct commander and the department's accreditation manager. He graduated from the FBI National Academy's 217th session in 2004, and the FBI Law Enforcement Executive Development seminar at Princeton University in June 2012.
His brother, Kevin Sarlo, also served the East Hampton Town Police Department, retiring as a captain in 2008 after a 23-year career. Two other brothers, Chris Sarlo and Rob Sarlo live in Virginia.
Michael Sarlo lives in Springs with his wife, Paula, and his children, Daniel and Melina.
"We have many challenges ahead, and I am looking forward to continuing to push our department forward," Sarlo said. "Chief Ecker has left us a top notch, professional police agency. I am looking forward to a smooth transition and have new ideas and initiatives we will be working on to provide the citizens of East Hampton the highest quality services."
Sarlo spoke highly of his predecessor, whom he called a mentor and friend. "Eddie's dedication and commitment to the community, and his dogged pursuit of justice has left a lasting legacy on the EHTPD. I would like to personally thank him for everything he has done for me, and my fellow officers," he said. "His leadership and example will be sorely missed, but we will carry on his legacy as a model for our agency."