Acting wasn't Karthi's cup of tea, though he had appeared in a scene in director Maniratnam's Aaytha Ezhuthu, in which he worked as an assistant director. However, his dad, veteran actor Sivakumar's insistence was what made him take up acting. Circa 2007, Paruthi Veeran happened. After Mounam Pesiyathe, an urban coming of age flick and Raam, a crime thriller, Paruthi Veeran was a completely new setup for director himself, but his conviction made sure, Paruthi Veeran turned out to be one of the most important films of Tamil cinema, and gifted Karthi a memorable debut.

For a youngster who had graduated in New York, Paruthi Veeran was a completely contrasting character, that demanded him to be unkempt, grow a thick beard, look mean and huge on screen and though Karthi was ready with the look, there were doubts if he could do justice to the rustic and rugged character. However, Karthi delivered an impressive performance smashing the doubts everyone had, as Ameer's strong character design gave him ample scope with a wide range of emotions.The warring, happy go lucky, jail crazy attitude of Veeran, the feelings he develops for Muthazhagu gradually and the way he expresses it,"Ingayum vandhuruchullaa", his anger on Kazhuvathevan and the challenge he makes and the finale where he expresses his agony and grieves over his deeds hitting him back by affecting Muthazhagu, followed by that ultimate brutal act, were portrayed excellently by Karthi, with reviews calling it as one of the best debuts of the decade, on par with the legendary Sivaji Ganesan's Parasakthi.

Karthi kept experimenting with unconventional scripts, and unique characters and his very second film Aayirathil Oruvan again had him in a rugged avatar as Muthu, a porter who gets entangled in a mysterious journey leading to the long lost Cholas, followed it up with different roles like the carefree guy in love Siva, who has to save his girl from threats and turns an action hero over a road trip in Paiyaa, a middle class youngster Jeeva, who can't stand his father's murder and silently completes his revenge in Naan Mahaan Alla, and then came his first complete mass role and that too in dual avatars as Rathinavel Pandian and Rocket Raja, a double treat for action and comedy lovers in Siruthai. With these first five movies itself, Karthi had turned a phenomenon, and a bankable hero.

After a brief lull in 2012-13 (when he went all out commercial) which had him playing a masterbrain who brings down a scheming politician in Saguni, an out and out mass hero in the masala entertainer Alex Pandian, Azhaguraja which had him trying a full length comedy role and Briyani which presented him as a playboy caught in a murder mystery, Pa.Ranjith gave the perfect resurrection flick for Karthi, with Madras(2014). His performance as Kaali, who unearths the hidden enemies exploiting his friends and people and brings them down was loved by the audience, and his decision to star in a socially relevant movie was appreciated by critics and audience alike.

And then came a variety of characters like the angry Kombaiya Pandian of Komban, the lovable,full of life Seenu who helps Vikramaditya (Nagarjuna) start living again in Thozha, the fraudster Kaashmora and the evil Rajnayak in Kaashmora which gave him an opportunity to present a menacing and evil act, the chauvinistic pilot VC who understands love after hurting his girl, to finally realize the feeling of loving someone more than himself in Kaatru Veliyidai. Though Kaatru Veliyidai gave him an opportunity to show the romantic side, the movie wasn't a commercial blockbuster. But that didn't stop Karthi from experimenting, as he chose to play a cop Theeran Thirumaran who's on a hunt to nab deadly dacoits, in Theeran Adhigaaram Ondru, based on real life incidents. He perfectly followed it up with a typical family entertainer with sentiments as well as mass elements in the perfect mix catering to all center audience in Kadaikutty Singam which was one the biggest blockbusters of 2018.

After back to back success with Theeran Adhigaaram Ondru and Kadaikutty Singam, shuttling between the class and the mass, next comes Dev from Karthi. This time around, he has teamed up with debutant maker Rajath Ravishankar, and the movie also stars Rakul Preet Singh, Ramya Krishnan, Prakashraj and Karthik in important roles. From the glimpse of Dev we've got in the teaser, the movie promises to be an interesting tale of a youngster who takes a break from his routine life and embarks on a journey filled with love, action, and self realization. Having worked with 17 directors in 17 films in his career spanning more than a decade, Karthi is expected to ace this time around as well, with his variety and lively performance in Dev. Given his track record and his knack of choosing scripts and unique roles, one can expect a cracker of an entertainer in Dev, releasing on February 14.