Disappointed that his career was hindered when he was forced by his family to put his education first, Karthik's father did not want his son to suffer the same fate and trained him hard from an early age.

[5] Karthik honed his reflexes at a young age by having his father throw hard leather balls at him at high speed.

He was initially a batsman and learned wicket-keeping on the Tamil Nadu youth teams, and Robin Singh considered him very fit.

[9] He got engaged to Indian squash player, Dipika Pallikal, in November 2013,[10][11] and they married in traditional Christian and Hindu ceremonies in August 2015.

[6] Karthik attended a wicket-keeping camp in the off-season under, guided by former Indian keeper and chairman of selectors Kiran More, which he credited with improving his technique.

[1] Karthik played in the inaugural season of the Indian Premier League as wicket-keeper for the Delhi Daredevils, scoring 145 runs with the bat at 24.16 and a strike rate[26] of 135.51.

Although Daredevils topped the tournament's pool stage, Karthik made only nine in the semi-final and his team were defeated by six wickets by the Deccan Chargers.

[45] He scored 14 runs in two innings and took two catches, but was praised for his wicket-keeping on a pitch with variable bounce and spin on which 40 wickets fell in two days.

He used his domestic experience to score 63 in the first innings, combining in a century opening stand and helping India to 414 (enough for a first-innings lead of 41).

[51] Although he did not play a match at the 2007 ICC Cricket World Cup,[52] after a roster reshuffle[53][54] Karthik was selected as a specialist opener for a tour of Bangladesh.

In the first Test at Lord's, Karthik made 60 in the second innings before India fell to 9/282 (in pursuit of 380) when rain ended the match early.

[49][61] He was recalled to the Test team as a wicket-keeper for the July 2008 tour of Sri Lanka when Dhoni took a sabbatical due to fatigue.

After watching the T20 and ODI series, Karthik played in the second Test when Dhoni was injured; he was criticised for dropping a number of catches.

[64][65] Karthik played in the 2004 ICC Champions Trophy against Kenya, taking three catches before being replaced on the ODI team by MS Dhoni.

After not batting in the victorious first match, he top-scored with 63 as a specialist batsman when India recovered from 35/3 to post 189 on a slow wicket at the Barabati Stadium in Cuttack.

[52] Selected for the inaugural 2007 ICC World Twenty20 in South Africa in September 2007, he played in India's earlier matches before being replaced in the semi-final and final by Rohit Sharma.

[74] During the series against England, he played in only the final match in Mumbai, making a duck as India scraped home by two wickets.

[52] Karthik had another chance in India's four-match tour of West Indies when he replaced Virender Sehwag, who was out with a shoulder problem.

[79] Karthik was retained for the 2009 ICC Champions Trophy in South Africa, but after his performances in Sri Lanka he was omitted for the first two matches.

Karthik kept wickets in the next two matches, scoring 32 and 19 (unbeaten in both) and helping guide India to the target in successful run chases.

Karthik retained his place for the ODI tri-series in Bangladesh against the hosts and Sri Lanka after Tendulkar was rested for the tournament.

[6] Karthik was recalled to the Indian ODI team for the 2013 ICC Champions Trophy after a good domestic season and IPL performance.

[81] The substitute, Patel, was included on the side before he injured his right index finger; Karthik began keeping the wickets on day four of the Test.

[83] Karthik was again named to the squad for the March 2018 Nidahas Trophy Tri-Nation T20 series, after team regular (and wicket-keeper) Dhoni was rested.

[89] The Tamil Nadu cricketer had a forgettable outing in the 2019 World Cup and, as a result, he was dropped from both the ODI and T20I squads post the quadrennial event.

[90] He outperformed expectations and stunned the world by scoring his maiden half-century in the format, 16 years after debut, in the third match of the series.

[91] In July, Karthik was named captain of the Indian side for the 20-over warm-up matches against Derbyshire and Northamptonshire ahead of the T20I series against England.

[93] However, Karthik failed to live up to expectations and had a poor outing with the bat, scoring only 14 runs in four innings, before being dropped for the rest of the tournament.

Though there was speculation Karthik would return to the national team after a strong showing at the IPL in 2024, he ended up not being selected and subsequently retired after the season in 2024.

Dinesh Karthik was also part of the commentary team during England-Sri Lanka T20I and ODI series held in July 2021.