While at Llanelli, Evans gained a call-up to the Welsh National Side and made his first international appearance as a right-wing for Wales against France in Paris in 1987. He went on to win 72 caps for Wales, 28 of which as a captain, and scored 33 tries – at that time a record for Wales – and was dubbed "Merlin" by TV commentator Bill McLaren. In March 1994, he captained Wales when the team won the Five Nations Championship.
Evans went on three tours with the British and Irish Lions, to Australia in 1989, New Zealand in 1993 and South Africa in 1997. Amongst his most memorable moments were scoring the decisive series-winning try in the 3rd Lions Test against Australia in 1989 and his four tries against the All Blacks in 1993, which made him the Lion's top try scorer. He made his final international appearance against Italy in 1998.
Evans was awarded the MBE for services to rugby in 1996, and announced his retirement from the game in 1999 to run his own PR marketing company. In 2007 he was inducted into the International Rugby Hall of Fame. In 2014 he was introduced to the IRB Hall of Fame.
After retiring from professional rugby, Evans has been a regular broadcaster, presenter and rugby pundit. He has worked for the BBC, ITV and currently for Sky Sports for over a decade. He has held a non-executive and ambassadorial positions for a number of companies and has been a board member of the Welsh Tourist Board, VisitBritain, 2010 Ryder Cup and Nominet Wales Advisory Group.
He is also involved in a number of charities. He contributed to a charity match in 2010, managing an international XV against England XV, raising funds for Help for Heroes. He has been actively involved in supporting Velindre Cancer Centre Wales. In 2010, he took part in the 'Captains Climb' which saw 15 past captains of the Welsh Rugby team climb Mount Kilimanjaro, raising thousands of pounds toward the work of the charity. Evans is also involved in Nicholls Spinal Injury Foundation, St John's Ambulance, Prostate Cymru, Sparks and is a Trustee and a Patron for Keep Wales Tidy.