The company was founded in December 2002 by Reid Hoffman and founding team members from PayPal and Socialnet.com (Allen Blue, Eric Ly, Jean-Luc Vaillant, Lee Hower, Konstantin Guericke, Stephen Beitzel, David Eves, Ian McNish, Yan Pujante, Chris Saccheri). In late 2003, Sequoia Capital led the Series A investment in the company. In August 2004, LinkedIn reached 1 million users. In March 2006, LinkedIn achieved its first month of profitability. In April 2007, LinkedIn reached 10 million users. In February 2008, LinkedIn launched a mobile version of the site.

LinkedIn's CEO is Jeff Weiner, previously a Yahoo! Inc. executive. Founder Reid Hoffman, previously CEO of LinkedIn, is Chairman of the Board. It is funded by Sequoia Capital, Greylock, Bain Capital Ventures, Bessemer Venture Partners and the European Founders Fund. LinkedIn reached profitability in March 2006. Through January 2011, the company had received a total of $103 million of investment.

A mobile version of the site was launched in February 2008, which gives access to a reduced feature set over a mobile phone. The mobile Service is available in six languages: Chinese, English, French, German, Japanese and Spanish. In January 2011, LinkedIn acquired CardMunch, a mobile app maker that scans Business cards and converts into contacts. In June 2013, CardMunch was noted as an available LinkedIn app. In August 2011, LinkedIn revamped its mobile applications on the iPhone, Android and HTML5. At the time, mobile page views of the application were increasing roughly 400% year over year according to CEO Jeff Weiner. In October 2013, LinkedIn announced a Service for iPhone users called "Intro", which inserts a thumbnail of a person's LinkedIn profile in correspondence with that person when reading mail messages in the native iOS Mail program. This is accomplished by re-routing all emails from and to the iPhone through LinkedIn servers, which security firm Bishop Fox asserts has serious privacy implications, violates many organizations' security policies, and resembles a man-in-the-middle attack.

In 2009, Syrian users reported that LinkedIn server stopped accepting connections originating from IP addresses assigned to Syria. The company's customer support stated that services provided by them are subject to US export and re-export control laws and regulations and "As such, and as a matter of corporate policy, we do not allow member accounts or access to our site from Cuba, Iran, North Korea, Sudan, or Syria."

In February 2011, it was reported that LinkedIn was being blocked in China after calls for a "Jasmine Revolution". It was speculated to have been blocked because it is an easy way for dissidents to access Twitter, which had been blocked previously. After a day of being blocked, LinkedIn access was restored in China.

Inspired by Facebook's "social graph", LinkedIn CEO Jeff Weiner set a goal in 2012 to create an "economic graph" within a decade. The goal is to create a comprehensive digital map of the world economy and the connections within it. The economic graph was to be built on the company's current platform with data nodes including companies, jobs, skills, volunteer opportunities, educational institutions, and content. They have been hoping to include all the job listings in the world, all the skills required to get those jobs, all the professionals who could fill them, and all the companies (nonprofit and for-profit) at which they work. The ultimate goal is to make the world economy and job market more efficient through increased transparency. In June 2014, the company announced its "Galene" search architecture to give users access to the economic graph's data with more thorough filtering of data, via user searches like "Engineers with Hadoop experience in Brazil."

At the end of 2013, it was announced that the LinkedIn app intercepted users' emails and silently moved them to LinkedIn servers for full access. LinkedIn used man-in-the-middle attacks.

In February 2014, LinkedIn launched its Simplified Chinese language version named "领英" (pinyin: Lǐngyīng; literally: "leading elite"), officially extending their Service in China. LinkedIn CEO Jeff Weiner acknowledged in a blog post that they would have to censor some of the content that users post on its website in order to comply with Chinese rules, but he also said the benefits of providing its online Service to people in China outweighed those concerns. Since Autumn 2017 are Job Postings from western countries for China aren`t possible anymore.

LinkedIn continues to add different services to its platform to expand the ways that people use it. On May 7, 2015, LinkedIn added an analytics tool to its publishing platform. The tool allows authors to better track traffic that their posts receive.

In November 2016, Russia announced its intention to block the network in its own country, as it "illegally stores data of Russian users on servers abroad." The relevant law had been in force there since 2014.

Soon after LinkedIn's acquisition by Microsoft, on January 19, 2017, LinkedIn's new desktop version was introduced. The new version was meant to make the user experience seamless across mobile and desktop. Some of the changes were made according to the feedback received from the previously launched mobile app. Features that were not heavily used were removed. For Example, the contact tagging and filtering features are not supported any more.