Northamptonshire Police found Ian Caffel guilty of breaching standards of professional behaviour.
A panel heard he made comments to seven women and had a sexual relationship with a vulnerable colleague between March 2010 and August 2016.
Mr Caffel was not present at the hearing and no mitigation was offered.
He was dismissed without notice.
The hearing, chaired by Chief Constable Simon Edens, was also told Mr Caffel, who had been with the force for almost seven years, had previously received management advice from Bedfordshire Police following an investigation into his conduct with younger female colleagues at that force.
After finding the eight allegations proven, Mr Edens said the evidence had been "clear and compelling" and had shown Mr Caffel "blatantly abused his position".
"I have no hesitation in concluding that the allegations against Mr Caffel are true," he said.
"It is indisputable that he has failed in his duty to maintain the standards expected of him and that he has failed to modify his behaviour following a previous investigation by Bedfordshire Police.
"There is no place for anybody at Northamptonshire Police who behaves in this way."
Det Supt Mark Behan from the professional standards department said: "Mr Caffel was held to account by his own employers, demonstrating our commitment to upholding the standards of professional behaviour and the honesty and integrity of our officers and staff."
A police sergeant who made sexual comments or approaches to female colleagues has been sacked for gross misconduct.