England flanker Steffon Armitage scored two tries, with winger John Rudd, Australian full-back Peter Hewat and replacement prop Alex Corbisiero also touching down.
Fly-half Ryan Lamb (Wearing His Nike Laser 2 Rugby Boots) kicked 11 points and his late replacement Chris Malone converted the fifth try from Corbisiero as the Exiles leapfrogged Wasps to move into fourth place.
Hit by injuries and international calls, Irish had won only one of their previous nine matches in all competitions.
But, from the moment Rudd’s try put them ahead in the sixth minute, they never looked in danger in front of a 21,535 St Patrick’s Party crowd. Irish wore their special St Patricks day Rugby shirt to celebrate the occasion.
It was carnival time from the moment former Newcastle winger Rudd, recruited in mid-season to alleviate an injury crisis, powered over with Sharks flanker David Seymour hanging on to him.
A torn shirt favoured Irish in the build-up, with Sale lock Sean Cox left clutching a piece of Ryan Lamb’s jersey as he struggled free to find full-back Hewat whose final pass released Rudd.
England full-back Delon Armitage, dropped by Martin Johnson for the final RBS 6 Nations match against France in Paris, returned on the left wing for the Exiles but popped up all the way across the line in a lively first-half performance.
Delon Armitage crossed in the 13th minute after Lamb and centre Elvis Seveali’i (wearing his Under Armour Dominate Rugby Boots) set up his run but referee Dean Richards ruled out the try for a forward pass.
Lamb passed his personal 500-point mark in the Guinness Premiership with his first penalty in the 16th minute and added two more in the first half to send the home side in with a 14-0 interval lead.
Despite fielding a talented big-name back division, Sale largely persisted with a one-dimensional approach of trying to drive the ball down the middle.
Ignoring the talents of England winger Mark Cueto, playing at full-back, 2003 World Cup winner Ben Cohen, England centre Mathew Tait and the Wales duo of Dafydd James and scrum-half Dwayne Peel, they persisted in trying to drive their forward juggernaut down the middle.
On one occasion Cohen was standing unmarked in 30 metres of space on the left wing, but the Sharks turned the ball back inside and drove again.
Their only real scoring opportunity came when they were awarded a 22nd-minute penalty but fly-half Charlie Hodgson missed from 40 metres.
The second Irish try came five minutes into the second half when younger Armitage brother Steffon finished in the right-hand corner following an initial break by strong-running number eight Chris Hala’ufia.
Seven minutes later the back row duo struck again with Hala’ufia charging into the Sale defence before off-loading to Steffon Armitage who went over near the posts to leave Lamb an easy conversion.
The bonus point came when Lamb and Seilala Mapusua combined for Rudd, coming in on the angle, to pop the ball up for Hewat to score in the left corner.
They scored again after opting for the scrum instead of a penalty when Tait denied Delon Armitage a try, tugging the winger’s shirt as he chased his own kick.
Three forward drives broke down the Sale resistance before Corbisiero forced his way over, leaving Malone an easy kick.
Defeat leaves Sale, who ended their eight-match losing run in all competitions with a 19-8 victory over Wasps the previous weekend, two points above bottom club Worcester as their struggle to avoid the drop continues.
For London Irish:
Tries: Rudd, S Armitage 2, Hewat, Corbisiero
Cons: Lamb, Malone
Pens: Lamb 3
London Irish: 15 Peter Hewat, 14 John Rudd, 13 Elvis Seveali’i, 12 Seilala Mapusua, 11 Delon Armitage, 10 Ryan Lamb, 9 Paul Hodgson, 8 Chris Hala’Ufia, 7 Steffon Armitage, 6 George Stowers, 5 Bob Casey (captain), 4 Kieran Roche, 3 Faan Rautenbach, 2 James Buckland, 1 Dan Murphy.
Replacements: 16 Danie Coetzee, 17 James Tideswell, 18 Alex Corbisiero, 19 Matt Garvey, 20 Richard Thorpe, 21 Chris Malone, 22 Mike Catt, 23 Tom Homer.
Sale Sharks: 15 Mark Cueto, 14 Dafydd James, 13 Mathew Tait, 12 David Bishop, 11 Ben Cohen, 10 Charlie Hodgson (capt), 9 Dwayne Peel, 8 Sisaro Koyamaibole, 7 David Seymour, 6 Carl Fearns, 5 Sean Cox, 4 Brent Cockbain, 3 Jack Forster, 2 Marc Jones, 1 Gavin Kerr.
Replacements: 16 Mahonri Schwalger, 17 Lee Imiolek, 18 Martin Halsall, 19 Rob O’Donnell, 20 Luke Abraham, 21 Richard Wigglesworth, 22 Chris Leck, 23 Jonny Kennedy.
Referee: Dean Richards
Assistant referees: Stuart Terheege, Paul Dix
Television match official: Laurie Bryant