It was the fourth straight domestic championship for PSG, sealed with no less than eight games and 62 days of the French season remaining.
Closest rival Monaco is an astonishing 25 points adrift after 30 games, closer to the relegation zone than the top of the table.
Ibrahimovic took his tally in Ligue 1 to 101 goals in just 115 games, underlining his importance for the Parisian giants.
The thumping victory capped a superb week for PSG, which reached the quarterfinals of the Champions League Wednesday with a 2-1 victory over English Premier League Chelsea.
The title was in the bag after three goals in six first half minutes at the Stade de l'Aube with Edinson Cavani, Javier Pastori, set up by a superb Ibrahimovic backheel and Adrien Rabiot scoring.
Ibrahimovic then took center stage, the 34-year-old Swede getting on the scoresheet for the first time just seconds into the second half.
His second was a mid-air volley from an Angel di Maria cross and he completed his hat-trick, his 100th Ligue 1 goal, with a swerving right foot shot.
An own goal, a Cavani goal after the Uruguayan saw his penalty initially saved and a fourth for Ibrahimovic from a Pastore through ball wrapped up the emphatic victory.
It was a fourth league title for PSG manager Laurent Blanc, having also guided Bordeaux to the 2008-09 title.
PSG has dominated French football since being purchased by cash-rich Qatari backers in 2011, enabling the capital side to attract the likes of Ibrahimovic, David Beckham and Di Maria and to make an impression at the top level of European club football.
Holder Arsenal exits FA Cup
In England, it proved a sorry Sunday for two-time FA Cup holder Arsenal, beaten 2-1 at home by fellow English Premier League side Watford.
With its EPL title hopes receding and trailing 2-0 to Barcelona after the first leg of the last 16 Champions League tie, the FA Cup was considered Arsenal's best chance of silverware this season.
But second half goals from Odion Ighalo and Adlene Guedioura proved decisive at the Emirates, despite a late rally by the Gunners.
Substitute Danny Welbeck pulled one back in the 88th minute then agonizingly saw another effort go wide after Alex Iwobi's shot hit the woodwork, Watford holding out out to reach the semifinals at Wembley.
Arsenal manager Arsene Wenger, who has faced some calls to step aside, was defiant in defeat.
"Our fantastic run has come to an end on a day where we felt that our performance deserved a win," the Frenchman told BBC Sport.
"Credit to Watford, they created few chances, but took them all. It's sad because we gave everything."
Wednesday will see his side take on European champion Barcelona in the Nou Camp.
Manchester United nearly joined Arsenal on the FA Cup sidelines later Sunday, coming from behind to salvage a 1-1 draw against West Ham at Old Trafford.
Dimitri Payet put the in-form Hammers ahead in the 68th minute with a stunning free kick, but United's young French striker Anthony Martial leveled 15 minutes later to earn a replay for Louis van Gaal's side.
Crystal Palace, 2-0 winners over Reading Friday and Everton, which beat Chelsea by the same scoreline Saturday, have already reached the last four.