The Welshman forced his way into a group of 16 riders on a punishing 185-kilometre course around Stamfordham. As the laps clicked off the group eventually whittled down, with Doull besting a small group sprint for bronze as two men stayed clear.
Connor Swift (Madison Genesis) launched a brave move with 13km to go and held off a late charge from Adam Blythe (Aqua Blue Sport) to take a memorable victory.
Tao Geoghegan Hart and Ian Stannard both attempted to bridge across to the breakaway group but were unable to haul back the committed leaders.
Elsewhere on Sunday Pavel Sivakov came home eighth in Russia. Christian Knees finished 17th from a bunch sprint at the German national road race, while Dylan van Baarle placed 19th in Holland after finding himself right in the mix on the final lap.
Saturday saw the Italian road race, with Salvatore Puccio leading the line for Team Sky in 11th, while Vasil Kiryienka secured Team Sky’s seventh national title of 2018 by winning the Belarusian time trial championship on Friday.