The win gives England a 1-0 lead in the seven-match series.
Pakistan opener Mohammad Rizwan scored 46-ball 68 to help the hosts to 158-7 in their 20 overs after England sent them in to bat at a capacity National stadium.
Pakistan’s players wore a special kit on which their names and numbers are shown submerged in water, to show solidarity with victims of the floods in the country.
England’s players wore black armbands as a tribute to Queen Elizabeth II who died earlier this month.
Hales, recalled from exile after injury ruled out Jonny Bairstow, smashed seven boundaries and added 55 for the fourth wicket with Harry Brook who finished on 42 not out.
Brook, one of seven England players to appear in this year’s Pakistan Super League, cracked seven boundaries in a robust 25-ball knock.
Ben Duckett (21), Dawid Malan (20) and Phil Salt (ten) were other England contributors.
Moeen Ali, standing in for injured tour skipper Jos Buttler, praised his bowlers for pulling back Pakistan from 87-1 after ten overs.
“It’s a brilliant performance,” said Ali. “We pulled the game back really well. A lot of praise to the bowlers who set it up nicely for our batters. Those crucial wickets around the 10th over made a difference.
“It wasn’t an easy wicket for the new batters. Luke Wood and Adil Rashid were excellent.”
Azam said his side lost momentum in the second half of the innings.
“The way we played the first power-play was great,” said Azam. “After 10 overs, there was a swing of momentum, which you have to credit England for, especially Rashid.”
Pakistan’s innings was once again held by Rizwan.
Rizwan, top run-getter in the Asia Cup earlier this month with 281, knocked six boundaries and two sixes and put on 85 for the first wicket with skipper Babar Azam (31) after England won the toss and fielded.
Iftikhar Ahmed hit three sixes in his 17-ball 28 but Pakistan managed just 71 runs in the last ten overs, losing six wickets.
Debutant Shan Masood failed with just seven runs while Haider Ali scored 11.
England debutant paceman Luke Wood finished with 3-24, while spinner Adil Rashid took 2-27.
The remaining matches are in Karachi (22, 23, 25 September) and in Lahore (28, 30 September and 2 October).