The 20-year-old playmaker has a deal in place to take him to Stamford Bridge at the end of the season.
An agreement has been reached at this stage as Chelsea were eager to fend off rival interest and secure the services of a much sought-after talent.
He will be on their books for 2019-20 and is being backed to thrive in the Premier League by a man who has seen him mature into one of the most highly-rated young performers in world football.
Dortmund’s sporting director Zorc told ESPN of Pulisic: "He's a lad who comes with that typically American self-confidence.
"He has the pace, he's got the dribbling, he wants to get ahead at all costs. I don't know a single reason why he wouldn't make it there."
A big-money transfer for Pulisic had been mooted for some time before Chelsea made their move.
Ever since bursting onto the Bundesliga scene, the United States international has been tipped for the very top.
Dortmund were always aware that they would struggle to keep a prized asset on their books, with Zorc conceding that the decision to cash in this year was made several months ago.
He added: "We took a collective decision with Christian's family and his agent that we would transfer him in the summer of 2019 if he didn't want to extend his contract with us.
"That decision was taken, and it then came to pass over the last few months.
"It wasn't a case of talks with Chelsea starting at Christmas and being concluded on New Year's Eve - this had been going on for weeks if not to say months."
Pulisic is preparing to bid farewell to Dortmund having been part of their first-team fold for three years and with well over 100 appearances to his name.
He has already expressed his excitement at preparing to head for England, with Chelsea considered to be a perfect fit, but is also determined to sign off in Germany with a Bundesliga title triumph.