Walker, who is attached to Dundonald Links in his native Ayrshire, had made the cut just once in seven events this season heading into the Emporda Challenge in Girona.
But the 26-year-old put some spring back in his step with a second-round seven-under 63 that contained nine birdies, including three to start and another three on the spin late on.
It was Walker’s best effort on the circuit by two shots and also represented a four-shot improvement on his previous lowest score this season.
“Yeah, really pleased,” said the former Walker Cup player of his day’s work, which saw him move close to the lead on six-under. “I mean, there’s not been that many great rounds this year.
“It’s quite bizarre because you just keep doing the same things and eventually you have a good round like today.”
Liam Johnston (65) and Bradley Neil (67) are also in contention heading into the weekend on four-under.
Howie, who had shared the lead after an opening 65, added a 70 in the second round of the Volvo Car Scandinavian Mixed event at Halmstad in Sweden.
The Peebles player sits just three shots off the lead, held by Australian Jason Scrivener after he stormed up the leaderboard on the back of a 64.
“I’ve come off the back of a couple of missed cuts, so it’s nice to be around for the weekend this time,” said Howie. “I’ve been working hard over the last couple of weeks and it’s nice to see that paying off.”
Scrivener leads by two shots from Sweden Linn Grant, a two-time winner on the LET this season, and Italian amateur Carolina Melgrati.
Henrik Stenson, who is hosting the event along with Annika Sorenstam, is lurking ominously, but, after opening with a 70, David Law withdrew before getting his second round underway due to an injury.
On the PGA EuroPro Tour, Michael Stewart tied for fifth behind English winner Nick Cunningham in The World Snooker & Jessie May Championship at Donnington Grove.