Treadwell also tasted Cheltenham Festival glory in the 2013 Byrne Group Plate aboard Williams' Carrickboy, but admits his National victory will always be the highlight of his career.
He said: "Growing up I always wanted to be a jockey and to ride in the Grand National, let alone win it, so that really was the ultimate - it was unbelievable.
"I will never stop looking back at that and appreciating how fortunate I was to win on my first ride in the race and get that opportunity for Venetia Williams and (owner) Vida Bingham. It was a fantastic day.
"I've had a fantastic journey through racing but in recent times with injuries and comebacks, I've just been feeling the pressures and I think it's the right time for a fresh challenge.
"Mentally it was draining, always putting on a brave face, and it was time to do the right thing for both me and my wife.
"It's been an emotional few days, just getting my head around the decision and I'll just take stock now, but I would like to stay in the industry, wherever that may be.
"I came into racing because I love horses and I love working with the youngsters and watching them progress, so perhaps that is something I will think about.
"I'm walking away on my own terms and I'm looking forward to the next challenge now."
Treadwell pulled up on his final ride at Warwick last Saturday and bows out with nearly 300 victories to his name.
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