Harvard dropout and tech evangelist Bill Gates, along with his childhood friend Paul Allen, founded Microsoft on April 4, 1975. 

Interestingly, Microsoft was not the first venture of Allen and Gates. The duo ran a company called Traf-O-Data ( founded in 1972) while still in high school.

The 1975 January issue of Popular Electronics magazine had a feature on the MITS Altair 8800 computer. After the article came out, Gates called MITs and offered to write a BASIC programming language for Altair. In just eight weeks, Allen and Gates demoed the program and MITS agreed to distribute and market the product under the name Altair BASIC. The deal incentivised Gates and Allen to start Microsoft as the former as its first CEO.

Evolution

In the fag end of 1985, Microsoft released Microsoft Windows and shifted the company headquarters to Redmond from Bellevue. It went public in March 1986. The iconic Microsoft Office suite was introduced in 1990. 

On January 13, 2000, Steve Ballmer took up the CEO mantle from Bill Gates. In 2014, Steve Ballmer stepped down as CEO. Indian origin Satya Nadella has been the head honcho of Microsoft since.

In early 2014, Microsoft acquired Nokia Devices and Services for USD 7.2 billion. In January 2022, Microsoft acquired game development company Activision Blizzard for USD 95.00 per share, in an all-cash transaction valued at USD 68.7 billion. Over the course of 47 years, Microsoft has made some major pivots. Windows OS single handedly drove the PC era. Later, internet explorer was the default browser for the internet age until Mozilla and Google entered the scene. The arrival of Satya Nadella was truly game changing for Microsoft. The tech giant got into the cloud business, and is now bullish on AI.