Weight and alcohol problems were to follow.
"I cannot say that I was born to be a jockey, I had to acquire the skills," he told journalists on a trip to Dubai in 2009.
"I was assigned to top trainer John Oxx, purely by chance. He was a good taskmaster who gave me a break. But above all I had the will to win.
"That is perhaps more important than anything else. I believe that even moderate riders can greatly improve their success with a bit of fine-tuning of the mind, by getting hungry."
Murtagh excels on the big occasion, having won many of the world's most prestigious races. His haul includes - in Ireland: two 2000 Guineas, two Irish Derbys, five Irish Oaks, two Tattersalls Gold Cups and an Irish Champions' Stake - in England: two 2000 Guineas, three Epsom Derbys, three Yorkshire Oaks, four Ascot Gold Cups, three King George VI & Queen Elizabeth Stakes and a Champions' Stakes - internationally: wins in the Prix de l'Arc de Triomphe, Breeders' Cup Turf, Breeders' Cup Mile and Hong Kong Vase.
He is a jockey to follow, particularly at Royal Ascot where he has scored at least once in all of the group one races staged there, including the Ascot Gold Cup (four times), Prince of Wales Stakes, Queen Ann Stakes (twice), St James Palace Stakes (twice), Coronation Stakes, King's Stand Stakes and the Golden Jubilee Stakes (three times).
"I would guess Sinndar and, perhaps, High Chaparral would be the best horses I have ridden, but I can't single out a specific win as my best. Every group winner is extraordinarily special, it's a feeling second to none especially of you had to fight hard or outwitted your rivals in the race.
"Last year, I had nice wins on Duke Of Marmalad, there was a stage during the season when he was in phenomenal form and nothing would have beaten him. I enjoyed riding him. I live for every new winner, it's my extreme passion."
It is documented that Murtagh fought a battle with alcoholism as a young jockey and he recounts: "Many jockeys have fallen prey to this. I was riding for John Oxx, made loads of money and had the world at my feet. So I partied hard, but it started telling and at 22, I had my first treatment for alcohol addiction."
Surely a jock is entitled to celebratory drinks?
"Where does alcoholism start and where does it end? One tot of booze was not enough for me, nor was 100 tots. But thank God I always kept my ambition. I knew that to be the best I had to conquer alcohol.
"I didn't want to be sitting broken in a pub at the age of 50 telling everyone what could have been, how good I was but how I never achieved what I wanted.
"So I took responsibility for my life and I've been without a drink now for more than seven years."
Murtagh stresses: "I'd like to bring this to everyone's attention. One can only develop as an individual once you take responsibility for your actions. The day I stopped blaming others for my problems, my life changed for the good. I saw the positive results immediately."
Indeed, life has become a journey of constant self-improvement.
"I am never 100 per cent happy with my riding. In racing, if you don't strive to improve every day, the others will catch up with you.
"In my younger days I spent time in America studying Gary Stevens and Steve Cauthen, in Australia I was fond of Mick Dittman. In Ireland, of course, I looked up to and today still admire the great Michael Kinane.
"I tweaked my style all along and I still need to make adjustments to stay ahead of the pack."
