Nationality	England
Position	Defender
Current Team	Yeovil Town
Birthday	04/09/1988
Age	36

Smith began his football career at Greenisland Boys Club under the management of his father and joined his first senior club, Ballyclare Comrades, in 2005. He signed for Ballymena United in January 2009, where he made over 100 appearances before moving to England to join Bristol Rovers in 2011.

At Bristol Rovers, Smith made his debut on 6 August 2011 in a 3–2 win against AFC Wimbledon. He played his first home game on 13 August in a 1–2 defeat to Torquay United. His first goal for the club came in August 2012, when he scored in a 3–1 EFL Cup loss to Ipswich Town.

Named the club's Player of the Year at the end of the 2012–13 season, Smith signed a new two-year contract. Despite the club's relegation from the Football League at the end of the 2013–14 season, following a 1–0 defeat to Mansfield Town, Smith and teammate John-Joe O'Toole were included in the PFA League Two Team of the Season. Smith subsequently requested a transfer.

On 25 July 2014, Smith signed a three-year deal with Peterborough United.

Smith joined Heart of Midlothian in the Scottish Premiership on 30 June 2017, signing a two-year contract and taking the number 2 shirt previously worn by Callum Paterson. On 7 January 2021, he extended his contract by 18 months, and in January 2022, he signed another one-year extension. He was announced to be leaving Hearts at the end of the 2022–23 season on 25 May 2023.

On 12 September 2023, Smith signed a one-year deal with National League South side Yeovil Town, with an option for an additional year. Following a successful 2023–24 season that saw Yeovil promoted back to the National League as champions, Smith had his contract extended by a year.