Schurrle, 22, has been on the radar at Stamford Bridge for over a year and is set to sign a long-term contract after the club confirmed a fee had been agreed on Thursday.
Chelsea midfielder Kevin de Bruyne has not been included as part of the deal, despite reports suggesting the Belgian would head in the opposite direction.
Hi, boss: Schurrle (right) was managed by Mourinho (left) in Michael Ballack's farewell match in Leipzig last week
On his way: Andre Schurrle has completed his £18million move from Bayer Leverkusen to Chelsea
Guitar hero: Schurrle's goal celebrations, in which he used the corner flag as an air-guitar, became a cult hit in Germany
Andre Schurrle factfile:
1990: Born November 2 in Ludwigshafen, Germany.
2006: After starting out with his hometown team, signs a deal with Mainz.
2009: Makes his Bundesliga debut for Mainz in a 2-2 draw with Bayer Leverkusen. Scores his first career goals a month later.
2010: September - Mainz announce Schurrle has agreed a five-year deal with Leverkusen from the end of the season. Makes his Germany debut shortly afterwards.
2011: Schurrle's final Mainz season ends with him scoring 15 goals - a club record.
2012: Plays for Germany at Euro 2012 but fails to score.
2013: April - Leverkusen confirm they have had contact with Chelsea about Schurrle.
June 13 - Chelsea announced they have agreed a deal to sign Schurrle.
2006: After starting out with his hometown team, signs a deal with Mainz.
2009: Makes his Bundesliga debut for Mainz in a 2-2 draw with Bayer Leverkusen. Scores his first career goals a month later.
2010: September - Mainz announce Schurrle has agreed a five-year deal with Leverkusen from the end of the season. Makes his Germany debut shortly afterwards.
2011: Schurrle's final Mainz season ends with him scoring 15 goals - a club record.
2012: Plays for Germany at Euro 2012 but fails to score.
2013: April - Leverkusen confirm they have had contact with Chelsea about Schurrle.
June 13 - Chelsea announced they have agreed a deal to sign Schurrle.
The Europa League winners confirmed the Schurrle deal and said in a statement: 'Chelsea and Bayer Leverkusen have reached an agreement for the transfer of Andre Schurrle, subject to the completion of legal documentation and related matters, including personal terms and passing a medical.'
Schurrle came through the youth ranks at Mainz where he played under Dortmund boss Jurgen Klopp and alongside Tottenham midfielder Lewis Holtby before leaving for Leverkusen in a £6.5m deal two years ago.
He made his international in November 2010, becoming the first player born in unified Germany to represent his country alongside Mario Gotze.
Schurrle plays predominantly on the left wing but is comfortable operating in any forward position. He has scored seven goals in 24 games for Germany.
Spending spree: Mourinho has made Schurrle his first signing since returning to Stamford Bridge
Staying put: Belgium's Kevin De Bruyne has not
been included in the deal to sign Schurrle, indicating that he will get a
chance to impress Mourinho in pre-season
International regular: Schurrle has earned 24 Germany caps since November 2010 and played at Euro 2012
New Blues boss Mourinho will now turn his attentions towards signing a striker, with Napoli's Edinson Cavani, Fiorentina's Stevan Jovetic, and Zenit St Petersburg's Hulk.
Chelsea are also keen on Wayne Rooney, who wants to leave Manchester United after growing unsettled at Old Trafford, but are unlikely to land their man with United unwilling to sell to a Premier League rival.
Wanted: Chelsea are also keen to land Edinson Cavani (left) and Stevan Jovetic this summer
