St Mirren Lappin was an unused
substitute in several games during St Mirren's 2000–01 Scottish Premier League campaign. After relegation that season he was fast-tracked into the first team where his crosses from the left, both in open play and from set pieces led to a number of goals for teammates. He made the first of his ten Scotland Under-21 appearances during 2003–04 the season and helped the club gain promotion to the
Scottish Premier League for
2006–07, after which he signed a two-year contract extension. He also scored one of St Mirren's goals as they defeated
Hamilton Academical 2-1 in the
2005 Scottish Challenge Cup final. Lappin made more than 170 appearances for the Buddies before he was signed by Norwich City manager
Peter Grant.
Norwich City with
Norwich City in 2010 On 31 January 2007, Lappin signed a two-and-a-half-year contract with
Norwich City for a £100,000 fee. He made his debut for Norwich on 3 February at
Carrow Road in a 2–1 win against
Leeds United, in which he earned the official sponsor's Man of the Match award. Lappin then scored his first goal for Norwich against
Luton Town on 27 February. City were awarded a free-kick in the 90th minute of the game at
Kenilworth Road, with the scores level at 2–2, when Lappin curled in a match-winning goal. Lappin played in most of Norwich City's games under Peter Grant in
2007–08, but when Grant was replaced by
Glenn Roeder Lappin found himself out of favour after a 3–0 defeat to
Plymouth Argyle. Lappin was one of six players criticised by Roeder after a 5–1 reserve-team defeat to
Ipswich Town. Lappin was
loaned to
Motherwell for the rest of 2007–08 on 31 January 2008. During this spell, he played 15 matches and scored two goals, including the only goal of the game in Motherwell's shock 1–0 win against
Celtic at
Celtic Park. Lappin remained at Norwich and despite the club's poor start to
2008–09, he still failed to get near the first team, even being made to train with the youths by Roeder. Many Norwich fans felt Lappin was being badly treated and should have been recalled to the team. After
Bryan Gunn's appointment as Norwich manager, Lappin made his first appearance for Norwich's first team in 16 months on 21 March 2009, in a 1–1 draw against
Birmingham City at
St Andrew's. Although his performances were not enough to prevent the club being relegated to
League One, Lappin signed a two-year contract extension with the club in June 2009. When
Paul Lambert took over as Norwich manager early in
2009–10, Lappin began to feature more regularly and ended up starting 42 league games, more than any other player, even captaining the side in a
Football League Trophy match with
Brentford when
Grant Holt and
Gary Doherty were both absent. Lappin continued to play a prominent role in the Norwich City side during
2010–11, signing another two-year contract extension in January 2011. By the start of
2011–12, players such as
Andrew Surman and
Elliott Bennett were regular choices, which resulted in Lappin only making four
Premier League appearances, along with two substitute appearances in cup competitions. This included deputising at left back for the last two matches following injuries to both
Marc Tierney and
Adam Drury. At the start of
2012–13, Lappin scored his first goal for the club in over five years in a
League Cup tie against
Scunthorpe United, beating
Sam Slocombe with a powerful effort from the edge of the box. He made his last appearance for the club on 5 January 2013, in a 3–0 win over
Peterborough United in the third round of the
FA Cup.
Cardiff City In November 2012, Lappin moved to
Cardiff City on an emergency loan until 1 January 2013. He made his debut for the club in a 2–1 victory at
Barnsley, but was sent off after picking up two yellow cards, the first Cardiff player to be dismissed in over a year. Following
Andrew Taylor's return to the side, Lappin was restricted to appearances on the bench, ensuring his second appearance for the Bluebirds didn't come until New Years Day in a 1–0 win at Birmingham City, which was his last before returning to Norwich the next day. In January 2013, Lappin was announced as a Cardiff player having left Norwich by mutual consent earlier in the month. In October 2013, Lappin signed for League One club
Sheffield United on a one-month loan. Having made five appearances for the South Yorkshire club in his first month, Lappin agreed to extend his stay until January 2014. With his loan deal close to ending, Manager
Nigel Clough insisted he would be willing to extend Lappin's loan spell until the end of the season. Following his loan spell at Sheffield United, Lappin never played for Cardiff again and at the end of the season, was released upon expiry of his contract.
St Johnstone After leaving Cardiff, Lappin was reported to be on trial with
Rangers in August 2014, however this was denied by Rangers manager
Ally McCoist. Lappin then signed a two-year contract with
St Johnstone. Upon signing, St Johnstone manager
Tommy Wright said that the club had signed Lappin ahead of other clubs who were interested, including one in
Major League Soccer in America. Lappin made his St Johnstone debut on 23 August 2014, coming on as a substitute for
Scott Brown in the 72nd minute, in a 1–0 win over
Aberdeen.
Later career On 16 November 2016, Lappin signed for
National League club
York City on a contract until the end of
2016–17. He was released at the end of the season, with the possibility of returning once recovering from a ruptured Achilles. Lappin signed for
Southern League Premier Division club
King's Lynn Town on 9 October 2017. He made his debut the following day, as an 81st-minute substitute in a 2–0 home win over
Hitchin Town. ==International career==