Ben Smith, 34, had completed 284 consecutive marathons in 284 days when he developed an umbilical hernia, in Aberdeen, on 10 June.
He set off from Inverness at 10:00 BST after medical care and following advice to "take time out and recuperate".
Mr Smith said he would use "everything in his power to be back on the road".
Since 1 September 2015, he had run 284 consecutive marathons in 284 days, covering 7,440.8 miles across 222 different locations across England, Wales and Scotland.
He said he would now need to cover an extra 2.5 miles a day for the next 106 days to make up for the time lost through injury - missing 10 days of running equates to 262 miles.
He said: "I was very upset the challenge had to be suspended especially when you think of all the hard work myself and the 401 team have put in over the last three years.
"Today I am feeling positive in both my mental and physical state and will no doubt use everything in my power to be back on the road."
He praised the "amazing" 401 team and said they would "deliver all the objectives we set out to do".
Mr Smith hopes to raise Â£250,000 for the anti-bullying charities, Stonewall and Kidscape.
The aim is to finish the run as planned on 5 October in Bristol.
A man who pledged to run 401 marathons in 401 days has resumed the challenge after 11 days off, recovering from a back injury.