Iain (45), who combines his work as a technician at Glasgow University with his part-time work in the Territorial Army, completed the 140-mile West Highland Way, with close pal David Smith, in just two days.
All the money raised from the sponsored walk will go to the Forces Children's Trust, which helps children whose parents have been killed or injured while serving in the Armed Forces.
And with 1,000 already raised Iain, from Kilncadzow, is hopeful that more people will recognise the work of the charity.
He said: "It was very hard going for myself and David (from Liverpool) because we were carrying packs that weighed around 15 kilos and it was very warm.
"We decided not to stop for lunch and eat on the hoof so by the time we got to Killearn where we were staying with friends we were really tired."
For more information on this article, see this week's Lanark Gazette which is in the shops now.