[8] Making his debut in the twenty20 format, Overton struggled with both bat and ball taking just four wickets and scoring a total of 35 runs from 10 matches.

[9] In 2015, Overton was the leading wicket-taker for Somerset in both the County Championship and the One Day Cup taking 47 and 12 wickets respectively.

During a County Championship match against Sussex in September 2015, Overton said "go back to your own fucking country" to Pakistani batsman Ashar Zaidi whilst bowling.

It was his third minor offence—following another report for abusive language in the previous match and physical contact in May—and Overton received an automatic two-match ban.

[16] During a Championship game against Hampshire, Overton made his maiden first-class century, scoring 138 as part of a stand of 217 for the eighth wicket with Roelof van der Merwe.

[27] In February 2018, he was added to England's ODI squad for their series against New Zealand, after Liam Plunkett was ruled out due to an injury.

[30] On 29 May 2020, Overton was named in a 55-man group of players to begin training ahead of international fixtures starting in England following the COVID-19 pandemic.

[31][32] On 17 June 2020, Overton was included in England's 30-man squad to start training behind closed doors for the Test series against the West Indies.