McElrath made his pro debut for the Troy Lee Designs Lucas Oil Honda team in the final three rounds of the 2013 AMA National Motocross Championship.
Competing in the 250SX West class, he recorded several top-10 finishes including a fifth in San Diego, with a final championship position of ninth.
McElrath missed part of the 2014 AMA National Motocross Championship due to a hematoma sustained at the opening round.
With one third place at race two in Glen Helen, McElrath finished in ninth in the final 250 standings at the AMA National Motocross Championship for that year.
A high point outdoors was that year's MXGP of USA, the final round of the 2015 FIM Motocross World Championship.
In the 2017 AMA National Motocross Championship he finished tenth in the final standings with an overall podium at the Budd's Creek round.
Another win at Salt Lake City later in the championship would secure him third in the final standings behind Aaron Plessinger and Adam Cianciarulo.
He finished ninth in the 250 standings in the 2019 AMA National Motocross Championship, where he won both races at the Budd's Creek round.
He signed for the SmartTop Bullfrog Spas Honda team but unfortunately a shoulder injury pre-season meant that he missed the majority of his 450 debut supercross season.
However, Rockstar Energy Husqvarna would sign McElrath for the 2022 AMA National Motocross Championship, as both of the team's main riders were out with injuries.
McElrath finished thirteenth in the final standings of the 2024 AMA Supercross Championship, qualifying and scoring points at all seventeen rounds.