The 25-year-old is one of several high-quality attacking players to have come out of France in the past few years.
He joined Leipzig in 2019 from Paris St-Germain after he realised he could not progress while in the shadow of Kylian Mbappe, Neymar and others.
Leipzig offered Nkunku regular playing time - he has averaged 42 competitive games per season over the past four years - and the chance to refine his game.
At first, the Paris native played as a winger under manager Julian Nagelsmann while occasionally being employed in the number 10 role.
Domenico Tedesco was the first coach who regularly fielded Nkunku as a striker and Marco Rose continued that tactic after replacing the now-Belgium manager last September.
While Nkunku was able to showcase his dribbling skills and agility in tight spaces when playing as a winger, he turned into a ruthless goalscorer in the central striker role.
He scored 35 goals in all competitions during the 2021-22 campaign and was named Bundesliga Player of the Season.
What Chelsea have acquired is a tactically versatile and technically highly proficient player who combines creativity with a drive towards goal.
Nkunku may make numerous stepovers and all kinds of dummies, but he is usually focused on getting the ball into the penalty area.
According to the analytics site FBref.com, Nkunku has been among the best 10 per cent of forwards in Europe's top-five leagues in several key statistics during the past calendar year, including non-penalty goals per 90 minutes, pass completion percentage and successful take-ons.
Mauricio Pochettino, who will officially take over at Chelsea on 1 July, has usually preferred a tactical system with one central striker.
Nkunku could well be employed in that role. With Kai Havertz expected to leave and Romelu Lukaku unlikely to return to Stamford Bridge, the Frenchman would seem to make the most sense for the position.
Equally, he could also be selected on the wing with a licence to roam to the inside. He displayed his tactical versatility during the recent German Cup final, which RB Leipzig won 2-0 against Eintracht Frankfurt.
Nkunku started the game as the lone striker in Leipzig's 4-2-3-1, holding the ball up and combining with Dani Olmo or Dominik Szoboszlai. During the second half he moved to the wing when Yussuf Poulsen came on to provide a more physical presence.
When he was employed in a wider area, Nkunku again showed his speed and progressive passing qualities. He also scored the opening goal as he drifted in from the left side in the 71st minute.
The Frenchman has made the most of his past four years in the Bundesliga.
However, while he has received praise for his performances, won two German Cup finals with Leipzig and received the trophy for the best goal scorer of the 2022-23 Bundesliga season, Nkunku has also had to deal with setbacks.
He suffered a ligament tear in his knee in the days before the World Cup in Qatar and was denied the chance to represent his home country in the tournament. While Mbappe and the rest were playing in the final against Argentina, Nkunku was working towards his comeback.
He looked rusty in his first few outings and had another setback when he suffering a torn muscle fibre.
After recovering from that second injury, Nkunku steadily improved his form, peaking in the final few weeks of the season as Leipzig secured a spot in the 2023-24 Champions League and won the German Cup final.
"Having played in Ligue 1 and the Bundesliga, I now want to play in the Premier League, one of the strongest in the world," Nkunku said on Wednesday.
He has been in the shadow of Mbappe and a other stellar countrymen in recent years, but the move to England and an ambitious and financially powerful club should offer Nkunku the stage to gain more international exposure and take his game to the next level.
