The adventurous father and son duo, from East Kilbride, South Lanarkshire, were up and down the summit within seven hours, taking several breaks in between.
Footage, filmed by Martin, 36, begins with Marcus at the foot of the mountain as he begins to make his ascent wearing his climbing gear.
The footage then follows the pair walking up the Stob Dearg stoney path, looking out over the stunning Scottish Highlands.
Marcus is then shown climbing the tricky Curved Ridge, using rope and wearing a climbing helmet.
The schoolboy is shown hauling himself up through each difficult stage of the climb while surrounded by up to 32ft drops at each stop point.
Marcus can then be seen nearing the summit, giving a cheeky wave to his summit, before he finally reaches the top and raises his arms to celebrate.
Proud dad Martin shared the footage on Facebook on Sunday, writing: “A wee video I made from yesterday with Marcus climbing Curved Ridge at 7-years-old.”
More than 300 viewers liked the post, with many leaving comments congratulating the youngster on his impressive achievement.
Anne L Camp wrote: “What a wee cutie, he’s amazing. Making that parent proud. Well done to you both.”
Alan Thurlow said: “You must be so proud. Fantastic experience, thanks for sharing.
“It looked amazing and professional with all the safety equipment, and of course you’re and excellent climber yourself. Well done gentlemen.”
Richie Iddon commented: An amazing experience for the wee man. Great to see him on an iconic ridge.
“We climbed it a couple of years ago and may have a go this winter. It won’t be too long before the wee man is climbing up there with no rope and on his own. Well done dad, great video.”
And Karen Devenport added: Epic dude. Awesome young man.”
Speaking today, Martin, a Reconnaissance Patrol Commander in the British Forces, said: “Marcus and myself have been doing this for 4/5 years now together. We only ever do it in great weather conditions and if he wants to.
“Curved Ridge was a different level for him. We broke it down into different levels and you could see the joy on his face when he reached his own mini goals.
“The reason we ended up doing Curved Ridge was because I mentioned to him one day whilst having lunch at The Kingshouse Hotel across from it that it was my favourite mountain.
“I told him about the climb and he said he wanted to do it. So that was enough for me. It was special to share that with him.”
Martin added: “For Marcus it was his most physically demanding route to date however he dealt with it better than some adults I’ve taken up that same route.
“After the climb he told me ‘my legs aren’t even sore.’ We then went home, had a movie night and the both of us crashed out around half past ten.”
“[He] has shown interest in climbing Ben Nevis as it’s the highest in the UK.
“I’ll maybe take him up via Tower Ridge. I think the next one for us is Aonach Eagach Ridge which is the narrowest in Britain, but we would break it up with a summit camp in the middle.”
Stob Dearg is the highest peak of Buachaille Etive Mòr, and one of the most famous sights of the Highlands standing 1,021 metres tall.