PC Steven Denniss, from Lincolnshire police, was off duty on 31 May last year, when he spotted a man wanted for a double-murder.
Daniel Boulton had stabbed his ex-girlfriend Bethany Vincent to death and her nine-year-old son Darren at their home in Louth the day before.
PC Denniss was walking his dogs when he saw Boulton standing next to a bench in a hooded top, staring at a member of the public.
The off-duty constable realised immediately that the man was the wanted murder suspect.
But as he approached him, he was attacked by Boulton, who ran off.
PC Steven Denniss Lincolnshire Police
PC Denniss was walking his dogs when he saw Boulton Lincolnshire Police
PC Denniss chased after him, calling an on-duty colleague on his mobile for back-up at the same time.
As he started to close in, the wanted murderer stopped and pulled out a knife.
He demanded the officer’s phone, before stabbing him in the leg and running off again.
Despite his injury, PC Denniss continued the chase, helping to guide colleagues to his location.
He then helped in clearing the public from the area for their safety while the suspect was tasered and arrested.
Last February, Daniel Boulton was sentenced to 40 years in prison for the double-murder and 21 months for the assault on the off-duty officer.
Daniel Boulton had stabbed his ex-girlfriend to death Lincolnshire Police
In passing sentence, the trial judge, Mr Justice Pepperall publicly commended the constable. He told the court: "I commend PC Steven Denniss for his bravery in seeking to arrest while off duty and without any backup or regard for his safety to protect members of the public."
PC Denniss beat 75 other nominations to awarded over all winner at the Police Federations National Police Bravery Awards.
Helen Stamp, Chair of Lincolnshire Police Federation, said: “PC Denniss’s actions demonstrate that he showed tremendous courage in tackling a man whom he knew had committed such atrocious crimes, putting the safety of the public before himself.
“Thankfully he was not seriously injured but he certainly went beyond the duties expected of him.”
Police Federation Chair Steve Hartshorn said: “Across England and Wales, day in and day out, our police officers are going to extraordinary lengths protecting the public.
"They go to work every day, never knowing what will be ahead of them. In the face of danger and adversity, they go above and beyond their call of duty to protect all of us.
“Their acts of courage go further than any of us could expect, the bravery shown is truly outstanding.
“They don’t do it for recognition or praise, they will tell you they do it because it’s their job.”