After university, Starmer-Smith briefly trained at a shipping management firm before choosing to focus on a career in rugby.
During the 1966-67 season, while still at Oxford he was selected to play for British rugby's foremost invitational team the Barbarians.
In 1969 he was selected to play for England against a touring South Africa side.
During the 2003 World Cup in Australia, Starmer-Smith commentated for ITV Sport's coverage.
On the 28 March 2021 edition of the BBC Radio 5 Live breakfast show, his son revealed that Nigel had been suffering from frontotemporal dementia since around 2015 and was living in a nursing home.