The 24-year-old scored twice in the space of five second-half minutes to put the Magpies 2-1 ahead after Tomas Soucek had given the Hammers an early first-half lead.
Newcastle's pressure after the break was rewarded when Isak equalised with a close-ranger finish, capitalising on a deflected header from West Ham's Edson Alvarez following a free kick from Kieran Trippier, who then set up Newcastle's No.14 for his second of the afternoon just after the hour mark.
Trippier this time side-footed an exquisite first-time volleyed cross from the right flank towards Isak, who poked his effort into the bottom corner from just a few yards out.
Isak came close to completing his hat-trick when he smacked the post in the final 15 minutes, but it was West Ham who had the last laugh in the 89th minute when substitute Mohammed Kudus smashed a low left-footed shot beyond Nick Pope to rescue a point at the London Stadium.
Isak has now scored five goals in his last five appearances for Newcastle this season and he has become the third Swedish player to score in three successive Premier League games after Freddie Ljungberg (a run of five goals for Arsenal in April 2002) and Zlatan Ibrahimovic (two three-goal runs for Manchester United in 2016-17).
Speaking to BBC Sport about Isak's impact in the draw with West Ham, Howe said: "[Alexander] Isak's hat-trick opportunity was probably the defining moment. He's an outstanding player.
"The first [goal] in particular is an outstanding finish. He is unlucky not to score the third but they are the small margins."
Isak came off in the final few minutes with an apparent knock and Howe is hopeful that the Magpies striker has not sustained a serious injury; Callum Wilson came on for the Swede despite not being at 100% due to a hamstring issue.
"I really only wanted to use Callum in an emergency, but Alex signalled that he had to come off so he was the natural replacement," said Howe. "Fingers crossed Isak is okay."
Reflecting on the point picked up against West Ham, Howe added: "A frustrating game for us. Probably a hangover from midweek. A really good response in the second half but we're frustrated not to get over the line.
"I think we did really well in the second half, showed great character to come back. We took control of the game, caused problems, created chances."
Newcastle remain eighth in the Premier League table heading into the international break, one point behind West Ham in seventh and four points adrift of the top four.
The Magpies will return to Premier League action when they welcome Crystal Palace to St James' Park on October 21.