Raised in Barrhead, Ashcroft was not picked up by a professional club as a youth and had transitioned into local amateur leagues when he signed for Kilmarnock in 2010.

[2] He made his senior debut for the club on 11 May 2013, as a substitute in a 3–2 victory against Dundee in the Scottish Premier League[3] and then four days later scored his first career goal in a 3–1 loss against Hibernian.

[9] His first goal for the club was versus Fife rivals Cowdenbeath in the same competition, where he scored from a Kallum Higginbotham free-kick.

[14] A regular starter throughout the season, Ashcroft scored his first competitive goal for the Dee in a Scottish Cup win against Bonnyrigg Rose Athletic.

[20] During a game against Motherwell in December 2021, Ashcroft would damage a tendon in his hamstring which would require surgery and keep him out for approximately 3–4 months.

[26] Ashcroft would start every game after in a very successful season which would culminate in scoring a goal in the win over Queen's Park which clinched the Scottish Championship title for the Dark Blues.

[36] The day following his departure from Dundee, Ashcroft joined Scottish Championship club Partick Thistle on a two-year deal.