He was just the second England cricketer to do so after Ken Barrington in 1964 and the first player from any country since South Africa's Gary Kirsten in 1998.
After more than 10 hours' batting, Root was eventually out when he skyed paceman Wahab Riaz and Mohammad Hafeez, running in from square leg, held a good catch to leave England 577 for seven on the second day of the second Test.
The highest individual score in an Old Trafford remains Bob Simpson's 311 for Australia against England in 1964, with the corresponding England record at the Manchester ground achieved in the same match when Barrington made 256.
Test match double hundreds at Old Trafford (score, player, country, opposition, year):
311 Bob Simpson AUS v ENG 1964
256 Ken Barrington ENG v AUS 1964
254 Joe Root ENG v PAK 2016
223 Gordon Greenidge WIS v ENG 1984
210 Gary Kirsten RSA v ENG 1998
205 Aamer Sohail PAK v ENG 1992