Luis Boa Morte, Yossi Benayoun and Marlon Harewood got the goals largely due to some suicidal defending, and Carlos Tevez had a key role in masterminding the victory.
It was a full house at the JJB Stadium with more than 5,000 Hammers fans making the trip north.
West Ham, rocked by the record £5.5million fine over the Tevez/Javier Mascherano transfer saga but happy to escape a points deduction, were given a lift with Argentinian star Tevez cleared to play.
Wigan had Scotland forward Lee McCulloch back after injury and Henri Camara in the starting line-up.
Both sides looked nervous early on and it was 16 minutes before Emile Heskey produced the first shot on target.
The big striker turned well but the shot lacked any sting and it was easy meat for Robert Green.
Tevez had a shot blocked by Emmerson Boyce, but there were problems for Wigan when a corner was only partly cleared and Mark Noble hooked over the bar.
The Latics suffered a big blow when captain Arjan de Zeeuw limped off after 25 minutes to be replaced by David Unsworth.
But they went close to breaking the deadlock when Boyce fired in the cross and leading scorer Heskey was just inches away with the header.
There was joy for the Hammers as they grabbed the lead on the half hour.
Boa Morte chased on to the ball from Lucas Neill and poked it over John Filan as he raced out and Boyce could only watch in despair as it bounced into the unguarded net.
West Ham almost had a second when Bobby Zamora's on target shot was blocked by Unsworth.
Wigan continued to live dangerously and Filan just managed to prevent a Tevez shot crossing the line after Boyce's block took the sting out of it.
But West Ham struck again when Wigan were caught on the break from their own free-kick.
Tevez and George McCartney were at the heart of a sweeping move before Zamora squared for Benayoun to slot it beyond Filan.
Tevez was then denied by the woodwork and Boa Morte's follow up was cleared off the line by Leighton Baines.
West Ham wrapped it up, again catching Wigan on the counter, and a move sparked by Tevez ended with Harewood being gifted the goal by Boa Morte.