Hugh Orde announced his departure from Northern Ireland in April
Electing police chiefs could lead to public confusion without improving accountability, said the head of the Association of Chiefs Police Officers.
Sir Hugh Orde, speaking in his new role as president of Acpo, said such a system could be targeted by protest voters from special interest groups.
"Every professional bone in my body tells me this is not a great idea."
The idea of directly electing senior police officers in some capacity is supported by the Conservatives.
Sir Hugh was addressing a Manchester conference in his new role as president of the association after announcing that he is stepping down as head of the Police Service of Northern Ireland later this year.
Prior to that, he was a deputy assistant commissioner with the Metropolitan Police and was short-listed for the commissioner's post earlier this year.
Sir Hugh said no-one could explain to him how an elected figurehead could better protect the public and offer greater accountability.
He said chief constables must "fiercely resist" any attempts to reduce them to "employee status" or interfere with their operational independence.
"To deliver, we must have a clear understanding of relationships between police, authorities and boards and government.
"If people seriously think some form of elected individual is better placed to oversee policing from the current structure, then I am very interested in the detail of how it is going to work."
Conservative shadow home secretary Chris Grayling said he wanted the Home Office to step back from micro-managing police chiefs but in return they must accept more democratic accountability.
Speaking at the same conference, Mr Grayling said he was not "wedded to a particular model" but wanted to see an election process creating a visible figurehead for policing in every area.
Sir Hugh said every police officer in Britain must already accept informal public scrutiny as images of their actions could be sent around the world in a "heartbeat".
"Policing has to get used to that degree of informal public scrutiny that will focus on individual actions and individual events."
His comments came as a report found police public order tactics used during the G20 protests were inadequate and should be reviewed.