"Before I was Philly McMahon, I was Phillip Caffrey," explains the Dublin footballer early in his autobiography 'The Choice'.
The book mainly deals with two relationships in McMahon's life: with Ballymun - where he grew up - and with his brother John who died in 2012.
It was the shame which he felt regarding his brother's heroin addiction which caused the five-time All-Ireland winner to change from Caffrey, his mother's name, to McMahon, his father's name.
Looking back now, McMahon can see under the facade of his brother's addiction to someone who remained a kind-hearted individual.
In his early youth, McMahon had looked up to John. That changed as his brother's addiction took over.
All he wanted to do was help, but I couldn't see that. I couldn't see that underneath it all he was still John, the big brother I adored. I couldn't see past the addiction. I was so embarrassed by him that I changed my name.
My mam and dad aren't married. Mam is a Caffrey, and we were all raised as Caffreys, but I was so ashamed of John, so ashamed to have a heroin addict in my family, as my brother, that I changed my name to McMahon, Dad's surname. I had been so proud to be Young Caffo growing up. Now I wanted to put as much distance between us as possible.
It was around the time that McMahon was beginning to get call-ups to Dublin development squads that he changed his name and started to push his brother away.
People in Ballymun might have been able to relate to what we were going through, but the further out of that circle I went, the more embarrassed I got. I was starting to get called into Dublin development squads, mixing with teenagers from all different parts of the city, and I was so aware that none of them had brothers who were addicted to heroin. It was eating me up. If they ever found out, I would have been humiliated.
'Here, are you Pillar Caffrey's son?' lads asked me.
'No no no' I explained. 'My name is actually Philly McMahon. It's only Caffrey by law.'
Now 30, McMahon views his brother's death as a major turning point, comparing it to a half-time team talk. On autopilot prior to the tragedy, he's now proactive in his life rather than reactive. Since John's death, he has made it his ambition to help people every day.
McMahon is no longer embarrassed to be John Caffrey's brother. He has appeared on the Late Late Show to talk about his brother's addiction and has become an activist for drug addicts, believing Ireland needs to change its perception of their affliction.
Picture credit: Piaras Ó Mídheach / SPORTSFILE
