Clever was the fourth-youngest capped Eagle at age 20 when he made his debut against Argentina in August 2003. That same year, Clever made his first trip to the Rugby World Cup as a member of the Men's Eagles, though he did not make an appearance. Four years and 15 caps later, he was selected to the USA's 2007 Rugby World Cup squad and this time was a full-time starter. In that tournament Clever intercepted a pass against South Africa that set up a famously long try by Takudzwa Ngwenya. In 2008, Clever captained the United States to Churchill Cup bowl win over Georgia and then clinched a 2011 Rugby World Cup birth by winning a home-and-away series against Uruguay. Clever would captain the Men's Eagles in the 2011 Rugby World Cup.

From 2004 to 2009, Clever was also a member of the Men's Eagles Sevens and made 24 appearances on the World Rugby Sevens Series.

Clever broke the record for most international test appearances by an American with his 68th cap against Russia in the summer of 2016.

His first taste at professional rugby came in 2006 with North Harbour of the National Provincial Championship in New Zealand. He would later become the first-ever American to play in the Super 14 (Super Rugby), as a member of the South African Lions. Clever would go on to play four years in the Japan Top League (Suntory Sungoliath, NTT Shining Arc) before leaving for the Newcastle Falcons of the Aviva Premiership. Clever is currently a co-owner and strategic partner for the Huns Rugby Management group and plays for the Austin Huns.