The former Millwall striker and boss joined the Welsh side in November 2019 and led them to a fifth-place finish last season, only for Cardiff to suffer defeat in the play-off semi-finals against Fulham, who went on to earn promotion.
This season has been far less of a success story, however, with just eight wins from 24 games leaving the team in 15th place.
Harris acknowledged the “pressure is on” this week in the aftermath of Cardiff’s defeat to QPR on Wednesday, which was a fifth-straight loss in the Championship and a sixth in a row in all competitions.
And his words proved somewhat prophetic, as he has not been given the opportunity to turn matters around against Barnsley next Wednesday.
A club statement thanked Harris and assistant David Livermore, who also departs, for their work but confirmed they had been dismissed due to poor results.
“Their efforts to propel us towards a fifth-place finish and Play-Off position last year are recognised and appreciated, although sadly we are in a result-orientated business and our on-field results of late and progress this season has been very poor. As such, we have had no choice but to relieve them of their duties in an effort to improve results and league position with a change of manager."
Owner Vincent Tan wished the pair well and noted that a new appointment would be confirmed in due course.
Following next week’s clash with Barnsley, Cardiff’s next game is against Millwall, the only other club Harris has taken charge of during his managerial career so far.