The Bournemouth T63 long jumper, 45, finished seventh in New Delhi after suffering an injury at the start of the competition.
But the south coast star, who lost both his legs when triggering a roadside device while serving in Afghanistan, powered through to complete all six jumps and record a longest distance of 6.41m.
Sinnott, who finished fourth on his global debut back in 2017, said: “I gave it everything but unfortunately, I got a nasty injury just before I started, so I’m wrapped up in a lot of painkillers at the minute.
“I’m glad I managed to stay in the top eight – I’m really chuffed with myself to achieve that.
“Ex military, you’re used to being in pain to be honest!
“Trying to perform at your top level while carrying injuries isn’t ideal – when big events come up you’ve got to put it all to one side, find that deep position and just go for it and give it everything.”
Sinnott is one of over 30 British athletes out in the Indian capital, with the team now sponsored by official finance partner Novuna.
He delivered a brave display at the Jawaharlal Nehru Stadium but was unable to hit the heights of Joel de Jong, Leon Schaefer and Daniel Wagner, who grabbed gold, silver and bronze.
Sinnott added: “They were tough conditions, brutal conditions.
“There were a lot of good jumpers there today.
“It was a good championship and a stacked event.”
Novuna is the Official Finance Partner of British Athletics and proud sponsor of the GB & NI Athletics Team. From everyday goals to world-class dreams, Novuna helps millions across the UK – backing British businesses, supporting individuals’ plans, and supporting British Athletics on the global stage. Find out more at www.novuna.co.uk
