[2] At Midland High School, Hoppel won the 2016 Texas 6A State Track & Field Championship with a time of 1:49.67, included an undefeated season in the 800 meters.

Upon the conclusion of his junior season, Hoppel announced he would forego his final year of NCAA eligibility to pursue a professional running career.

After completing a full three seasons of collegiate running, Hoppel secured a 4th-place finish in the 800 meter final on October 1, one year and one month after his season-opening cross-country race at the Bob Timmons Invitational on September 1, 2018.

On 15 February Hoppel earned his first national title at the USA Track & Field Indoor Championships, held in Albuquerque, New Mexico, running a time of 1:46.67 to win the 800 m final.

In August, he competed in the Monaco Herculis meeting, where he was narrowly defeated by fellow American and reigning 800 metres world champion Donavan Brazier.

A few weeks later on February 6, at the New Balance Indoor Grand Prix, he placed second in the 800 m with a time of 1:46.08 behind Spaniard Mariano García.

In Belgrade, Hoppel earned a bronze medal, placing third behind Mariano Garcia in first, and Noah Kibet in second, running a tim eof 1:46.51 in the process.

He was unable to replicate that successful showing at the World Championships the next month in Eugene, placing fourth in his heat and not advancing to the semi-finals.

On 4 February, Hoppel competed in the short track 1000 metres at the New Balance Indoor Grand Prix, finishing in a time of 2:16.91 behind Marco Arop's new North, Central American and Caribbean area record of 2:14.74.

[9] Hoppel, along with his training partner Hobbs Kessler, and Brooks Beasts athlete Brandon Miller, were named the men's 800 meter Team USA representatives for the 2024 Summer Olympics.

[11] Finishing ahead of Hoppel was Algerian Djamel Sedjati in 1:41.50, Canadian Marco Arop in 1:41.20, and Kenyan Emmanuel Wanyonyi, who won the race in 1:41.19.

[12] On February 8, at the Millrose Games, Hoppel finished second to Josh Hoey in the men's indoor 800 meters, running 1:44.19.