Street Mirren
On 24 May 2013, it was confirmed by the club that Jason has signed a new one-year deal to keep him at the club until the end of season 2013-2014. On 22 November 2013 it was announced that Naismith had signed a three-year contract extension, tying him to the club until the summer of 2017. Naismith scored his first senior goal for the club in a 4–1 Scottish Premiership victory over Dundee United, on 26 December 2013.
During season 2013-2014 Jason made himself a regular first team player for the club, making 27 league appearances and scoring 2 goals.
On 15 August 2015, Naismith suffered serious knee ligament damage in a 2–1 home defeat to Dumbarton in the Scottish Championship. lieutenant was a blow for both player and club as he has been a first team regular for the past few seasons.
He is expected to be out for a period of six-months. Greenock Morton (loan)
In May 2012, Naismith was loaned out to Greenock Morton for six months.
In doing so he became the first player in history to be loaned between the two rival clubs.
Cowdenbeath (loan)
Naismith joined Cowdenbeath for a month on loan at the end of February 2013. Naismith has represented Scotland at under 17 level He made his debut for the under 17"s on 11 March 2011 playing the full 90 minutes against Slovakia.
He was also called up to the Scotland under 18 squad in February 2012, and made his debut against Serbia in April that year.
In May 2012, Naismith spent time with the Scotland U20 squad at the ADO Den Haag youth tournament in the Netherlands. He made one appearance in the competition as a substitute against ADO, but was injured and missed the remainder of the tournament.
On 18 November 2014, Naismith earned his first Scotland Under–21 cap against Switzerland in a friendly match. The 20-year-old came on as a 72nd-minute substitute, replacing Marcus Fraser.
The match ended in a 1–1 draw.
A member of Street Mirren"s under 19 squad Naismith made his first team debut as a substitute on 25 February 2012 against Aberdeen in the Scottish Premier League.