Dan Connolly, from Catstree in Worfield, near Bridgnorth, took on 1,200 runners and 60 horses at the Man v Horse event in Llanwrtyd Wells on Saturday.
The event, put on by food company Whole Earth, has taken part in the Welsh town since 1980 when the landlord of the Neuadd Arms Hotel pub overheard two men discussing the relative merits of men and horses running over mountainous terrain.
Last weekend, Dan completed the 22-mile trail in two hours, 24 minutes – 10 minutes in front of the first horse.
He is only the fourth person to beat the horse in the event’s 42- year history.
The first horse, DNS Ronaldo, was ridden by Kate Atkinson and took two hours, 34 minutes and 25 seconds.
On crossing the line, 6ft 4in (1.93m) Dan had no idea whether he had won as the people and animals take different routes.
He said afterwards: “A great day out in the beautiful Welsh hills, suffering in the heat amongst my favourite animals.
“Since I started running, I’ve had an eye on doing Man Vs Horse one day. As I just missed out on the World Championship in Austria, I was looking for an inspiring event to keep the fire burning hot. The timing was right.”
He added: “I very happy to have beaten the horses but also to have shared a wonderful day with my family. I can’t recommend this event enough, such a beautiful community.
“Thank you to the organisers and well done to all who took part. Leaving with a smile on my face and some achy legs.”
Organiser Bob Greenough said: “It’s the first time the event has been won two years in a row by a runner, and only the fourth time overall in 42 years of the race.
“It was an incredibly hot day. The event went remarkably well. Everyone is in very good spirits.”
The first woman across the line was Suzy Whatmough who did it in three hours, eight minutes and 24 seconds.