The 81-year-old, from Finglas, was reported missing in Ireland on July 29.
His body was spotted in the water at South Shore around three weeks later.
However, due to the condition of the body, detectives struggled to formally identify him.
Det Sgt Kathryn Riley, of Blackpool CID, said: “On August 17, a call was received from a member of the public who thought they could see a body in the sea opposite the Glitter Ball.
“The body was recovered but there was no ID.”
At around 9pm on the night he went missing, Mr Kennedy went to put the bins out at his home. That was the last time he was seen alive.
Police in Ireland investigated more than 250 reported sightings but no trace of him was found until his body washed up in Blackpool.
Det Sgt Riley added: “It has taken police and forensic services a number of weeks and months to be able to extract DNA.
“As a result of liaising with the Missing Persons Bureau in the UK and in Ireland and making inquiries in relation to the brands of clothing the deceased male was wearing, it was felt he may well have originated in Ireland.
“We were then given a possible ID for the man and we have now got confirmation.
“This is a tragic situation for the family but it is a little bit of closure at last that we have identified Mr Kennedy’s body.”
A statement posted on a Facebook page set up to help find Mr Kennedy said: “It’s with great sadness that we would like to inform you that the body of Thomas Kennedy has been recovered.
“Tommy’s family would like to extend their thanks to people from all over the country who have been involved in the effort to bring him home.
“Our condolences to family and friends of Thomas.
“Thanks to everyone for all the help and support. RIP Thomas xx”
In August, a Dublin taxi driver told Irish police he believed he may have picked up Mr Kennedy shortly after midnight on the night he went missing near his home in Virginia Park.
The driver took the man from Finglas to Baldoyle, where one of Mr Kennedy’s sons lives. Despite moving the search to that area of the country, police were unable to determine Mr Kennedy’s movements before he died.
Mr Kennedy’s death is not being treated as suspicious and an inquest will take place in Blackpool in due course.