The British rider joined Team Sky as a neo-professional in 2017, having coming through the Axeon Hagens Berman development team. He has steadily progressed and this year caught the eye with a number of strong domestique performances for team leaders in week-long stage races.
Geoghegan Hart was key to propelling Egan Bernal to victory at the Colombia Oro y Paz in February and the Tour of California in May, and then turned heads at the Critérium du Dauphiné, when he was the last rider with overall winner Geraint Thomas on the key mountain stages.
"I've gained more and more WorldTour experience and I'm starting to get closer to a few more significant results. I've been chipping away on that front and I've also gained experience in different roles," Geoghegan Hart said in a statement from the team.
"I was fortunate enough to be road captain in a few races this year and then have a protected status in a few others. I've also been working for some of the bigger names in the team in other races so there's been some nice variety in that sense. I've learned some big lessons but overall I'm happy with how it's gone."
Of the Dauphiné, Geoghegan Hart said: "To see Geraint so dominant with the Tour coming up and to see how he rode was pretty special to be a part of. That was the biggest race that I've done in my career up until that point, so to come away with the win at the end after four big mountain stages was something I'll remember for a long time."
Geoghegan Hart told Cyclingnews in June that his ambition was to move down the Team Sky mountain train in the coming years, and eventually become a protected rider and leader himself.
Having made his Grand Tour debut at this year's Vuelta a España, the 23-year-old is aiming to continue his progression in three-week races, with the 2019 Giro set to be the next step. Sky's Grand Tour plans have not yet been confirmed but it is likely the team will go to Italy targeting overall victory with Bernal, Thomas, or Chris Froome.
"Looking to improve in terms of Grand Tours is probably my biggest ambition," Geoghegan Hart said. "Then also on a more personal level I'm hoping to keep stepping forward in the week-long WorldTour level stage races. California was a really great race this year and I missed a podium on GC by a few seconds lost getting held up behind a crash on a sprint stage. If I can rectify small things like that next year it will lead to bigger and better results.