Gambhir captained Kolkata Knight Riders to win IPL titles in 2012 and 2014, and later mentored them to the feat in 2024.

Gambhir was coached by Sanjay Bharadwaj of Lal Bahadur Shastri Academy in Delhi, and Raju Tandon.

[14] Gambhir was signed up by the Delhi Daredevils franchise in the first player auction of the Indian Premier League for US$725,000 a year.

[21] Under Gambhir's captaincy, the Kolkata Knight Riders qualified for the IPL playoffs and also made it to the Champions League Twenty20 for the first time.

[23] During the same season, he scored 6 half-centuries out of a total of nine from his team and became only the second player to cross the 2000 runs mark in the history of the IPL.

[24] He led the Knight Riders to their second title in 2014 by beating Kings XI Punjab in the final by 3 wickets.

Later Kolkata Knight Rider's CEO Venky Mysore revealed that Gambhir had asked the team not to retain him as he wanted to finish his IPL career where he started.

[26] On 25 April, Gambhir stepped down from captaincy citing poor performances of the team, and announced Shreyas Iyer as the new captain of the Delhi Daredevils.

However, he was not selected for the 2007 World Cup as the selectors opted for a top-order of Sourav Ganguly, Virender Sehwag, and Sachin Tendulkar.

It affected him badly and Gambhir later said that "When I got dropped for the World Cup, there were times I didn't want to play anymore.

In the 2007–08 CB Series, he scored an unbeaten 102 at the Gabba against Sri Lanka in a match washed out due to rain.

In 2008 Gambhir finally solidified his place in the Indian Test team with a string of high scores.

Opening the batting with Delhi teammate Virender Sehwag, he scored 858 runs at over 61 in seven matches as of December including a double century against Australia in the Border–Gavaskar Trophy.

This innings led Virender Sehwag, Gambhir's opening partner, close friend, and captain for the match, to call him 'The Second Wall' in reference to Rahul Dravid.

He then scored 167 in the second innings of the Third Test to give India an unassailable lead, but rain helped the New Zealand batsmen to hang on for a draw.

Gambhir withdrew from the Third and final Test against Sri Lanka at the Brabourne Stadium in Mumbai in order to attend his sister's wedding.

[39] In 2010, Gambhir was appointed captain of the national team in the ODI series against New Zealand which was hosted by India.

He scored an unbeaten 126 in the third match in Vadodara to help seal the series, guiding the hosts to victory in the run-chase.

Out of sixteen innings in away Tests, India passed 300 just twice and both the team's opening batsmen failed to score a century in the format in the whole of 2011.

In the same period, only two opening batsmen who had played at least 15 innings had a worse average: Phillip Hughes of Australia and Imrul Kayes of Bangladesh.

However, while he was struggling in Tests, Gambhir enjoyed a rich run of form in ODIs, averaging 56.90 from 23 matches.

[45] On 14 February 2012, against Sri Lanka, Gambhir yet again missed out on an ODI hundred when he was dismissed run out for a fine 91 off 106 balls.

[50] Gautam Gambhir began his new innings as a parliamentarian as he took oath as the Lok Sabha MP on 17 June 2019.

On July 9, 2024, Gambhir became the new head coach of The Indian Men's Cricket Team replacing Rahul Dravid.

He set up community kitchens in 2017 through the Foundation in Patel Nagar, Delhi, in a bid to make sure no one slept hungry in the city.

The key project of the Foundation is to reach out to as many children of paramilitary martyrs as possible and empower them by supporting their entire educational needs.

The scheme, called "Gambhir ki Rasoi," aims to provide hot meals to people who are facing financial difficulties due to the COVID-19 pandemic.

[52] On 22 March 2019, he joined the Bharatiya Janata Party (BJP) in the presence of Union ministers Arun Jaitley and Ravi Shankar Prasad.

[58] On 2 March 2024, he announced that he has requested BJP National President JP Nadda to relieve him of political duties as he wants to focus on cricket commitments.