Hamilton was more than half a second quicker than Red Bull Racing’s Max Verstappen in second and a dispiriting 0.652 seconds faster than teammate Valtteri Bottas, who will start third.
The Briton’s lap time of 1 minute 31.304 seconds was also a new track record for the Sochi Autodrom.
But qualifying wasn’t all plain sailing for championship leader Hamilton, who almost suffered an embarrassing exit in 15th after his first lap of Q2 was deleted for exceeding track limits - he remains under investigation for improperly rejoining the track - and his second was interrupted by a red flag triggered by Sebastian Vettel crashing his Ferrari.
When the session resumed Hamilton had a little over two minutes to make it out of his garage and begin a flying lap. He ran wide at turn two and was baulked by another car at the final corner, but he scraped over the line with less than two seconds on the clock and eventually progressed to Q3.
But the last-gasp lap came at a cost. The Briton had to use the delicate soft-compound tyre, which he must now start the race with. Chief rivals Bottas and Verstappen will start on the longer-lasting medium compound.
“[It’s] not good,” he said. “That’s definitely going to make it hard to win the race.”
The long run to the first braking zone will also leave him vulnerable to being slipstreamed into turn two, compounding his potential woe.
“It’s nice being on pole, but here’s probably the worst place to be on pole,” he said. “I’m most likely I’m going to be dragged past tomorrow.”
Verstappen agreed with the Briton’s pessimistic assessment.
“I think if we can have a decent start, then the tow effect is very big around here,” he said. “If I can get a good draft, who knows what’s going to happen into turn two.”
Despite being confounded by the 0.6-second gap to his teammate, Bottas too felt positive his fortunes could improve markedly at lights-out.
“It’s a pretty good place to start third, and I’m starting on the right tyres,” he said. “I really think I have an advantage with the medium tyre in the first stint, so still all to play for.”
Though Bottas starts directly behind Hamilton and is best-placed to seize the slipstream, he starts on the second row alongside Sergio Perez, whose Racing Point will be shod by the grippier soft tire off the line and may complicate the race to the apex.
Daniel Ricciardo leads Renault-McLaren for the French manufacturer, qualifying fifth alongside Carlos Sainz’s McLaren in sixth.
Teammates Esteban Ocon and Lando Norris followed in seventh and eighth respectively.
AlphaTauri’s Pierre Gasly qualified ninth ahead of Thai driver Alex Albon’s Red Bull Racing machine.
Charles Leclerc was Ferrari’s quickest driver and will start 11th alongside AlphaTauri’s Daniil Kvyat.
Lance Stroll was withdrawn from Q2 with a technical problem, leaving him 13th on the grid beside George Russell’s Williams.
Sebastian Vettel qualified 15th for Ferrari after crashing at turn four, the Ferrari driver spinning backwards after clattering the apex kerb and smacking into the barriers.
Romain Grosjean will start 16th for Haas after being knocked out of Q1 by half a second.
Alfa Romeo’s Antonio Giovinazzi will start 17th alongside Haas driver Kevin Magnussen in 18th.
Nicholas Latifi qualified 19tth for Williams ahead of Kimi Raikkonen, the Alfa Romeo driver force to abandon his final qualifying lap thanks to a mistake at turn two.