Rahm entered the day at two under par following a superb opening-round 68 that featured no bogeys, but he was unable to build on that momentum as Oakmont's difficult conditions took their toll.
The 2021 US Open champion dropped six shots between the 12th and 16th holes, with the damage capped by a nightmare double bogey at the par-four 16th. Rahm found a bunker off the tee and then repeatedly failed to escape trouble, sending three consecutive shots into the sand before eventually carding a six.
His frustrations had already begun to show earlier in the round. After missing a short birdie putt at the ninth hole, Rahm reacted angrily, loudly shouting a familiar expletive, as his hopes of staying in contention began to fade.
The collapse saw the Spaniard tumble from two under to six over par for the tournament, leaving him outside the cut line and ending his hopes of securing a first major title since joining LIV Golf in 2023.
Rahm had arrived at Oakmont among the favourites after finishing runner-up at last month's PGA Championship, but a difficult day on the greens proved costly.
Wyndham Clark will take a formidable four-shot lead into the weekend at the US Open, with the world's top two players Rory McIlroy and Scottie Scheffler both trailing the leader by seven strokes.
Wyndham Clark surged four shots clear at the US Open after Thursday's rain-affected opening round, while Rory McIlroy began steadily and Scottie Scheffler has some work to do.
Rory McIlroy will begin his quest for a second major title of the year alongside Ryder Cup teammates Tommy Fleetwood and Ludvig Aberg.
Designed by William Flynn in 1894, Shinnecock Hills is one of the US Open’s most famed host venues – and is also feared for being among the toughest of all of them.
