Despite not catching the eye when initially joining Rafa Benitez's recently relegated outfit, he quickly changed the opinions of the Geordie faithful, receiving the club's player of the year award as United lifted the Sky Bet Championship trophy in 2017.
Having put pen to paper on a new deal at St James' Park, VAVEL take a look at what makes Clark such an important player to Newcastle United.
A goalscoring defender
Clark may have been brought in to help keep goals out, but during his four years on Tyneside he has also been a threat at the other end, particularly from corners.
With over 100 Magpies appearances to his name, Clark also has 11 goals during his time with the club, however he has only scored the once so far in the 2020/21 season and that came in the 5-2 drubbing against Leeds United at Elland Road back in December.
In a side that lack goals, Clark's set-piece threat is an asset to the club and it was something that the players worked tirelessly on under Benitez, less so under the new boss Bruce.
A left-footed centre-half
Left-footed centre-backs are sought after at many clubs across the world but Newcastle don't exactly have an abundance themselves with Clark and Paul Dummett the only left-footed players who can play in that position in Steve Bruce's defence.
Centre-back is typically deemed an unglamorous position to play in but the position shows why Clark is so valuable to Newcastle. His hard work and grit can not be disputed and Bruce should really make the most of the Irish international's experience in yet another area of the pitch where the Mapgies are struggling.
Clark is reliable and can be forgiven for his heavy touch which helped Arsenal open the scoring in the recent Emirates FA Cup tie between the two sides. He had helped his team to keep the likes of Pierre-Emerick Aubameyang and Alexandre Lacazette quiet for the 90 minutes of normal time after all.
Errors from Clark have been few and far between during his time at St James' Park.
One aspect about Clark's deal is that he is a relatively low earner compared to the majority of Premier League players - something that Newcastle owner Mike Ashley won't particularly be bothered about.
Putting Ashley aside, this should in theory help to free up a budget which can enable the Magpies to tempt some players who perhaps play in the more 'glamorous' positions on the pitch, usually in the form of loans as that's how it works at Newcastle United.
If anything, it could be argued that being a relatively low earner, in football terms anyway, takes that pressure off Clark's back knowing that he isn't stealing a living by putting in poor performances every week.
What is for sure is that Ciaran Clark is certainly a valuable player to the team and it is positive news that he has signed a new contract with the club.