The Arizona-based Scot, who was forced to miss this summer's Olympic Games, claimed victory in Sunday's Denver Half-Marathon in his first race in almost nine months, recording a time of 1hr 6min 12sec.
It has been a long road back to full health for the 29-year-old, who has battled through hamstring and cramping problems over the past two years.
"It was a great comeback race for me," said Lemoncello. "To be honest, I would have been happy just to finish and be pain-free. So getting the win was a big bonus for me."
The Fifer will next run in Edinburgh on October 7 where he will face Britain's Olympic steeplechaser Stuart Stokes over 10km. "It promises to be a close encounter and I'm sure Andrew will be very eager to produce something special in front of his home fans," said race organiser Peter Riley.