Animal Rights Action Network (ARAN) says it has been 'inundated' with calls of support for John Byrne since the Herald's story on Monday.
John dived off O'Connell bridge to rescue his pet rabbit Barney, after a passer-by had flung him off the bridge into the River Liffey.
He told the Herald this morning that he "cannot believe" he is going to be presented with the award on Tuesday.
"Ever since the Herald wrote about what happened, myself and Barney have been getting so much support.
"But to be given an award is unbelievable. It's nice to know that despite living on the street, people still care and want to do a nice thing for me,"
John Carmody of ARAN told the Herald that John's actions was one of the most 'admirable' things he's ever seen.
"We have been swamped with calls of support ever since the Herald broke the story. People were just taken aback by John's bravery.
"To think that he jumped off O'Connell bridge for his rabbit just shows how compassionate he is.
"It has sent a shiver down my spine for such a touching act of kindness. This award is only presented to one person each year and there's no doubt John deserves it. I urge everybody to get out there on Tuesday and support him."
Mr Carmody added that he believes John and Barney's ordeal will help their cause to lobby for stricter measures against animal cruelty.
ARAN campaigners are already planning to attend Dublin District Court on July 21 where the teenager who flung John's rabbit into the Liffey will face charges.
The 18-year-old was charged with a public order offence as well as animal cruelty. Garda Shona Moran of Store Street station, who arrested the teen involved, will be present at the presentation on Tuesday which takes place at 12.45pm on O'Connell Bridge.
John says the events on Sunday have changed his life.
The Herald revealed on Wednesday how the owner of a pet farm in Tipperary has already offered him a job and a place to stay for Barney.
"It's great to be asked, you never know what I'll do," John joked.