Simmons was born in Luton, England, to English parents and moved to Stittsville, Canada with his family at the age of five.[1][2] He began playing youth soccer at age six with Goulbourn SC.[3] Afterwards, he joined the Ottawa Fury Academy at age nine.[4][5]
At age ten, he attended a scouting camp led by the West Ham Academy and was invited to England where he trialed with the West Ham and Arsenal youth systems, before ultimately joining the MK Dons academy in March 2010.[6] At the age of 16, he continued his development at MK College where he was regularly called up to the England Colleges side.[5] In 2016, he joined the FC Málaga City Academy in Spain.[7] In 2017, he played with the U19 and U21 teams of Swedish club Dalkurd FF.[8]
In January 2019, he signed with HFX Wanderers FC of the Canadian Premier League.[11] He had had other others to remain in Europe, but chose to return to Canada, intrigried by the opportunity to play in the league's inaugural season.[12] At the end of the season, he departed the club.[13] In November 2019, he went on trial with Swedish club GAIS.[14]
In February 2020, he signed with Cavalry FC.[15][16][17] In November 2020, Simmons re-signed with the club for the 2021 season and also spent the offseason training with Swedish Allsvenskan club Östersunds FK.[18] On June 30, 2021, he scored his first professional goal in a match against Atlético Ottawa.[19][20] In January 2022, it was announced Simmons would return for the 2022 season, his third with the club.[21]
In December 2022, he signed with Vancouver FC ahead of the 2023 season.[22][23][24] In January 2023, Simmons joined Championship club Huddersfield Town on a training stint.[25] In September 2023, he was named to the CPL Team of the Week for the first time.[26] After the season, he went on a training stint with English National League side Barnet, as well as another club in the same league.[27][28] In May 2024, he departed the club by mutual consent.[29][30]
Simmons is eligible to represent Canada and England internationally. In his youth, he played five games with the English Colleges FA.[5]
In September 2015, he made his debut in the Canadian national program, attending a training camp with the Canada under-20 team, subsequently attending another camp in January 2017.[3]