Born in
Edinburgh, Buchanan made his breakthrough in football at
Cowdenbeath, progressing through their youth system to play in the first team. Buchanan was prolific for the
Central Park club, finishing top goalscorer in seasons
2005–06 and
2006–07. Buchanan then signed for
Partick Thistle at the start of the
2007–08 season. Buchanan was the
Firhill club's top scorer that season, despite suffering a long-term injury early in 2008 and being out until October that same year, when he played in his return match against
Airdrie United. Buchanan predominantly played in the number 9 shirt and was thought to be the next big prospect at the club. Buchanan notched 14 goals in that first season, from 27 starts and three substitute appearances. In January 2011, Buchanan signed for
Dunfermline Athletic. Buchanan helped the club win the
2010–11 Scottish First Division that gained promotion to the
Scottish Premier League. The club finished bottom of the table in the
2011–12 Scottish Premier League season and were automatically relegated into the
Scottish Football League First Division. In August 2012, it was confirmed that Buchanan had rejected a new contract with Dunfermline and signed for
Sligo Rovers. On 7 December 2012, Buchanan signed for
Airdrie United. Buchanan left Airdrie on 10 January 2013 and then signed for
Ayr United until the end of the
2012–13 season. On 26 July 2013, Buchanan signed for
East Fife. After one season there, he signed for
Alloa. Buchanan then spent two seasons with
Livingston, where the club were relegated and subsequently promoted the next season to the
Scottish Championship. Buchanan, however, remained in
Scottish League One, signing for recently relegated club
Raith Rovers on 9 June 2017. On 7 June 2019, Buchanan signed for Alloa Athletic for a second time. On 22 June 2022, Buchanan signed for
Berwick Rangers of the
Lowland Football League. In his first season outside the SPFL, he was the Lowland League's top goalscorer with 22 goals.{{cite web|title=Season over for Berwick Rangers after cup knockout After a strong start to the 2023-24 season, including a hat-trick against Edinburgh University, Buchanan earned a move back to the SPFL at the age of 38.{{cite web|title=Berwick Rangers claim third win in a row thanks to hat-trick by Liam Buchanan against Edinburgh University ==Career statistics==