[2] Born in Guatemala, he attended Armijo High School in Fairfield, California,[3] where he was a state champion in cross country and track.

[3] His senior year, Grijalva signed a letter of intent to compete for Northern Arizona University (NAU), beginning in fall 2017.

[9] In June 2021, Grijalva turned professional after securing a sponsorship deal with shoe company HOKA ONE ONE, and he remained in Flagstaff, Arizona to continue training under his college coach, Mike Smith.

Grijalva competed internationally in June over 3000 m on the Diamond League, running to a time of 7:38.67 and a sixth-place finish in Stockholm, Sweden.

[16] Grijalva competed in several European races during June and July, including at the Golden Gala Pietro Mennea meet in Italy.

He placed 4th for the second time in the 5000 m of a global championship, just 0.22 second shy of bronze medalist Jacob Krop of Kenya.

[19] In March, Grijalva competed at the The TEN in San Juan Capistrano, setting a new Guatemalan national record of 27:26.02.

[23] In October, it was announced that he had signed up for the inaugural season of the Michael Johnson founded Grand Slam Track.