The Peveril, on East Quay and Crown Street, announced the news on Sunday, with many expressing their sadness and sharing pictures and memories.
Alfie lived a full and adventurous life, spending much of his 17 years prowling the grounds of Peel.
He was the successor of the equally famous Peveril pub cat Smudge.
The Peveril has been in the hands of the Kelly family for 32 years, with three sisters Karen, Dawn and Vicky running the historic boozer after the retirement of parents Kevin and Christine.
The Kellys shared their memories of Alfie who had captured the hearts of locals and visitors alike with his charming personality and mischievous adventures.
‘It has been really lovely to see all the many Facebook messages about Alfie. He really was quite a famous cat!’ said Karen.
‘We got him quite soon after losing Smudge in 2006, and he was soon quite at home in The Peveril.’
Customers of The Peveril, and not just regulars, will remember Alfie's presence in the pub. Despite the hustle and bustle of busy days, Alfie was known for holding court in his favourite seat, much to the delight of patrons.
Away from the pub, Alfie was a busy cat. From hunting rabbits in the castle, long-tails on Peel Hill to waiting for the bridge to swing along with the people holding whatever unfortunate creature he had caught in his mouth.
And he certainly had his favourite spots for treats, including the Marine kitchen door for scraps and the fish bar on Weatherglass Corner (Spit Corner) for his daily prawn.
And as mentioned previously, Alfie certainly had a mischievous side.
Karen said: ‘He had his own chair to sleep on in the old antique shop behind the Peveril.
‘He basically slept wherever he liked which resulted in him being found in such places as fishing boats, a fisherman’s car on the way to Ramsey and once even the lifeboat as they prepared to launch!’ ‘Alfie was very well-loved, and although the way he went wasn’t what you’d want, you couldn’t have asked for a better life!’ said the Kelly family.
People commented on the emotional post sharing their personal memories of Alfie.
One read: ‘So sorry to hear this, he was great company when I was working at the castle. He often gave visitors tours around the best rabbit holes.’
Another added: ‘So sad, he was such a character. Lovely boy. Fearless with dogs but loved punters. Such a shame.’