Teams had already spent a combined £1.005bn as of 08:30 BST on Wednesday, shattering last year's record £870m. Thirteen top-flight teams broke their own transfer records.
The 20 clubs in the Premier League have benefited from a record £5.1bn television deal which came into effect this season.
"As has been the case for a number of years now, the increases in broadcast revenue, with the 2016-17 season being the first of the new broadcast deal cycle, is the principal driver of this spending power," said Dan Jones, a partner at financial analysts Deloitte.
This graphic below illustrates the gradual increase in spending by Premier League clubs over the past 10 January and summer transfer windows.
The average gross spend for a Premier League club in the 2016 summer window was about £60m
The total of £155m spent by Premier League clubs on deadline day broke the previous record of £140m set during the summer 2013 window
The four Premier League clubs competing in this season's Champions League - Arsenal, Leicester City, Manchester City and Tottenham Hotspur - had a combined gross transfer spend of about £385m - representing about a third of the aggregate gross transfer spend by Premier League clubs
Since the introduction of the transfer window system, gross player transfer spending has exceeded £8.6bn, with more than 80% of this being spent in summer transfer windows
Not only did this year's figure of £1.165bn break the record set this time last year, but it also dwarfed the £215m spent during the first window in the 2003-04 campaign.
Such financial strength owes much to the record £5.136bn domestic TV deal, which was more than £2bn larger than the previous contract, which ran from 2013 to 2016.
Ex-England winger Trevor Sinclair said: "There's so much money in it for a reason - supply and demand.
"People demand to see the Premier League. If anyone is going to get the financial gain, surely it has to be the players, they are the ones who make it happen."
Below is a list of the biggest fees spent by Premier League clubs during the 2016-17 summer transfer window:
Clubs flex financial muscle
The clubs who broke their transfer records
Manchester United: Paul Pogba (£89m) Bournemouth: Jordon Ibe (£15m)
Liverpool: Sadio Mane (£36m) Sunderland: Didier N'Dong (£13.6m)
Crystal Palace: Christian Benteke (£32m) Hull: Ryan Mason (£13m)
West Ham: Andre Ayew (£20.5m) West Brom: Nacer Chadli (£13m)
Leicester: Islam Slimani (£29m) Watford: Roberto Pereyra (£13m)
Southampton: Sofiane Boufal (£16m) Burnley: Jeff Hendrick (£10.5m)
Swansea: Borja Baston (£15.5m)
The two Manchester teams each spent more than £150m in the window.
Manchester United, under new boss Jose Mourinho, ended what was becoming a protracted saga by signing Paul Pogba for a world-record £89m.
They also added Armenia midfielder Henrikh Mkhitaryan and Ivory Coast defender Eric Bailly, both at a cost of about £30m.
City, who also have a new manager at the helm in Pep Guardiola, brought in midfielder Leroy Sane from Schalke for £37m and then paid Everton £47.5m for defender John Stones.
After a previous season that could be classed as terrible, Chelsea owner Roman Abramovich gave another new managerial recruit - Antonio Conte - new spending powers.
In an effort to rejoin the Premier League's top four, the Blues spent £120m, including £34m on bringing back Brazil defender David Luiz from Paris St-Germain and £33m on Belgium striker Michy Batshuayi from Marseille.
Elite clubs loan out elite players
This was also a window when clubs vying for a top-four spot sent players out on loan who, only last season, were seen as first choice.
About £153m worth of talent, based on the fees paid for them, found temporary homes in this window.
Manchester City led, with keeper Joe Hart, midfielder Samir Nasri, striker Wilfried Bony and defender Eliaquim Mangala shipped out. They have a current estimated market value of about £62m.
Chelsea loaned out 38 players - five more than this time last season. Midfielder Juan Cuadrado, who cost £23.3m, signed up to another season at Italian champions Juventus, and £6m-forward Lucas Piazon will spend his 2016-17 season at Fulham. It is the fifth club the Blues have loaned the 22-year-old out to.
Chelsea defender Nathan Baxter, 17, will be playing for Metropolitan Police until January, who play in the Isthmian Premier League - the seventh tier of English football.
Meanwhile, West Ham's £12m forward Enner Valencia will ply his trade at Everton this season and Arsenal's England midfielder Jack Wilshere, who has made more than 100 appearances for the Gunners, has relocated to Bournemouth.
Championship heavyweights spend big
There was a record £215m gross spend by Championship clubs, more than twice the previous record. However, the disparity of wealth between last season's relegated clubs and seasoned Championship campaigners was once again highlighted.
Newcastle and Aston Villa made use of the £64m parachute payments - guaranteed after dropping down a division - and spent more than £110m between them during this window.
Villa's outlay was more than £60m. It included the £11m spent to buy striker Jonathan Kodjia from Bristol City - that might rise to a Championship-record fee of £15m - and the £12m paid to Fulham for forward Ross McCormack.
The Magpies finished the window with a net profit of more than £30m, despite spending more than £54m on players. That was largely as a result of the Championship-record £30m deadline-day sale of midfielder Moussa Sissoko to Tottenham.
Norwich City, who lost a year's worth of parachute payments having stayed in the Premier League for only one season, spent about £15m.
Wolves, under new Chinese ownership, paid a club-record £7m for Monaco forward Ivan Cavaleiro - that was the 13th signing of the summer, bringing their total spend to £14m.
By contrast, league newcomers Burton Albion spent a club-record £300,000 on midfielder Jackson Irvine from Ross County.
The English Championship was in fact the fifth-biggest spending league in Europe, beating the amount spent by France's Ligue 1.
The graphic below shows the order of the amount spent by Europe's 'big five' top-flight divisions.
After the Premier League, the next highest spender was Serie A, with a gross spend of £590m. Then came the Bundesliga with a spend of £460m, followed by La Liga (£400m) and Ligue 1 (£165m).
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How social media reacted
So which player involved in transfer activity caught the most attention on social media?
It was Brazil defender David Luiz who has returned to Chelsea from Paris St-Germain.
There were 330,000 tweets about him, followed by Arsenal's Jack Wilshere, who was sent out on loan to Bournemouth. There were 108,000 tweets about the midfielder.
Manchester City keeper Joe Hart, now on loan at Torino, Tottenham's new signing Moussa Sissoko and Arsenal's Samir Nasri, who was sent to Sevilla, were the other hot topics.
BBC reports.
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