Al-Muwallad began his career at the youth teams of Al-Ahli before joining the Ministry of Sport's scholarship programs to develop football talents in 2021.[2] Following his return from the scholarship program, Al-Muwallad joined Saudi First Division League side Al-Okhdood on a one-year contract on 13 July 2022.[3] He made 31 appearances and scored twice in the 2022–23 season, helping Al-Okhdood earn promotion to the Pro League for the first time in their history.[4] Al-Muwallad was also awarded the Young Player of the Season award.[5] On 14 August 2023, Al-Muwallad made his Pro League for Al-Okhdood debut in a 1–1 draw against Al-Shabab.[6] On 9 September 2023, Al-Muwallad renewed his contract with Al-Okhdood until the end of the 2025–26 season.[7]
In October 2023, Al-Muwallad was called up for the Saudi Arabia national team for the first time ahead of the friendlies against Nigeria and Mali.[8] He was an unused substitute in both games. In November 2023, Al-Muwallad was called up for the 2026 FIFA World Cup qualifiers against Pakistan and Jordan.[9] On 21 November 2023, Al-Muwallad made his debut for the national team in the 2–0 win against Jordan. He came off the bench in the 65th minute replacing Saleh Al-Shehri.[10]
