In his freshman year, he averaged 11.8 points and 7.8 rebounds per game for Father Tolton before being a key figure in helping them win the Missouri Class 3 State Championship for the first time during his sophomore season.

During Jontay and Michael's time at Nathan Hale High School, the brothers were coached by former NBA All-Star Brandon Roy, who helped lead the squad to a perfect 29–0 record and the Washington Class 3A State Championship.

Under the coaching of Roy, Porter averaged a double-double of 14.3 points and 13.6 rebounds per game for Nathan Hale High School, thus earning a name for himself alongside his older brother.

Between his time preparing for his transfer from high school into college, Porter grew two more inches, thus allowing him to play as a power forward, with center being a viable possibility as well.

Sources: Porter, five days before his 18th birthday, made his season debut on November 10, 2017, in a 74–59 win over Iowa State University.

One week later, Porter recorded his first collegiate double-double with 11 points and 11 rebounds in a 67–62 win over Emporia State University.

On January 10, 2018, Porter made his first start of the season for Missouri, recording a double-double of 15 points and 10 rebounds in a 68–56 win over the University of Georgia.

However, unlike Michael Porter Jr., he entered the draft without hiring an agent first, thus allowing him the possibility to return to Missouri for another year if he was willing to do so.

[18] On November 3, 2022, Porter was named to the opening night roster of the Wisconsin Herd, the G League team affiliated with the Milwaukee Bucks.

[24] On March 25, 2024, ESPN reported that the NBA had opened an investigation of Porter for "multiple instances of betting irregularities over the past several months".

On March 20, during a game against the Sacramento Kings, the NBA said Porter "disclosed confidential information about his own health status" to an individual known to be a sports bettor.

[31] On June 4, 2024, Long Phi Pham, an alleged co-conspirator in Porter's scheme, was arrested at JFK International Airport while attempting to flee the country.

[34] On July 3, 2024, court papers were made public revealing Porter's imminent criminal charges in the United States at the federal level for his role in the sports betting scandal, which then resulted in his lifetime NBA ban.

[38] One of the conditions related to his guilty plea was to forfeit his passport for a pre-sentence release, which forbade him to play overseas for the Promitheas Patras B.C.