Only five Britons have more Olympic medals than Farah, who also won six world, five European and two European indoor titles as well as the Chicago Marathon in a career dating back more than two decades.
Farah waved to the crowd during the final 200m of the Great North Run before jogging back down the finishing straight to high-five fans, many of whom were carrying 'One Mo Time' signs.
"Without the crowd I wouldn't have got through it," he said.
"I wanted to end my career here in Newcastle. I've had some amazing memories. It's really important to come out here and give my support to the crowd.
"It's very important to have a race like this. Without the support and community in Newcastle, it wouldn't be the same."
Former European 10,000m champion and Great North Run founder Brendan Foster said: "Mo Farah is the greatest sportsman or woman Britain has ever had. We'll never see his type again."
Steve Cram, the former 1500m world champion and now BBC commentator, said: "Thank you for the memories. Thank you for the medals. Thank you for all the excitement and drama."
British Athletics described Farah, who was knighted in 2016, as "the greatest", while Team GB tweeted: "Generation: inspired."
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