He took the biggest win of his career to date on the 2012 Omloop Het Nieuwsblad, attacking fiercely twice. The first attack came on the Molenberg climb, thinning the field, and he attacked again on the 'Lange Munte' cobbled section to reduce the lead group to only two competitors, Juan Antonio Flecha and Tom Boonen. He outsprinted them to claim the victory.
In 2013, Vanmarcke was focusing on the Classics, but he injured his knee in a crash at Tirreno–Adriatico, which hindered his form for the first important one-day races of the season. He nonetheless participated in the Tour of Flanders, finishing 3 minutes in arrears of Fabian Cancellara. A week later, he finished second to Cancellara in Paris–Roubaix. He escaped with Stijn Vandenbergh after cobbled sector 6 but was joined later on by Cancellara and Zdeněk Štybar. On the cobbled section Carrefour de l'Arbre, Štybar and Vandenbergh were dispatched one-by-one because they collided with spectators. Vanmarcke lost the 2-man sprint contested in the velodrome and was emotional afterward, since he had come so close to victory.
2014
In 2014, Vanmarcke showed excellent form in the classics, with fourth place in Omloop Het Nieuwsblad and third in Kuurne–Brussels–Kuurne the following day. He also recorded top five finishes in E3 Harelbeke and Gent–Wevelgem. In the Tour of Flanders, Vanmarcke was the only rider able to follow Cancellara's attack on the final climb of the Paterberg. The pair caught up with the two earlier escapees, Vandenbergh and Greg Van Avermaet. The race came down to a sprint between the four, with Cancellara emerging victorious ahead of Van Avermaet and Vanmarcke.
2015–2016
Vanmarcke failed to score a top 10 finish at the monuments in the 2015 season but placed 5th at Omloop Het Nieuwsblad, 4th at Strade Bianche, 5th at E3 Harelbeke and 6th at Gent-Wevelgem. In his final season at in 2016, Vanmarcke finished on the podium at the Tour of Flanders, and 4th at Paris–Roubaix. He was also 8th at E3 Harelbeke and finished 2nd at Gent–Wevelgem. He achieved his best result of the season at the Ster ZLM Toer winning stage 4 and the overall.
Cannondale–Drapac (2017–present)
For the 2017 season, Vanmarcke returned to his former team that he had raced for in the 2011 and 2012 season. He finished 3rd at Omloop Het Nieuwsblad, but crashed out at the Tour of Flanders which also prevented him from starting in Paris–Roubaix. However he returned to the peloton later on in the season and almost won the National Road Race Championships. Vanmarcke's first podium of the 2018 season came at Omloop Het Nieuwsblad, where he finished 3rd. He then went on to finish 7th at E3 Harelbeke before claiming 3rd at Dwars door Vlaanderen. At the Tour of Flanders, Vanmarcke was once again struck with bad luck as he punctured several times at the start of the race. He only finished 13th but, a week later at Paris–Roubaix he finished 6th. He finished 5th at the NationalRoad Race Championships before lining up for his 5th Tour de France in July.
