Mr Tennent, whose previous best year of running was about 2040km, said the challenge had seen some unexpected benefits.
"I'm 56 years of age, I've been running for coming up 10 years and I managed to take over three minutes off by best time for a half marathon and over 14 minutes off my personal best for a marathon. I did about 18 or 19 events over the year and the eight or nine that I had done before, I beat my time in every single one.
"It really comes down to just doing more ks."
Mr Tennent said he first got into running in his mid-40s in a bid to speed up some weight loss to get off a diet quicker.
He said both his father and uncle had died in their 50s so he knew he needed to do something about his lifestyle.
Mr Tennet said while he ran road events, his love was trail running.
"I probably would have given up if I hadn't have discovered trail running."
Now that he has completed the 2015 goal he plans to take it a step further, this time running 2016 miles in 2016 in this year's Strava challenge.