Adnan Masud Syed was born in Baltimore, Maryland, United States to Muslim parents Rahman Syed and Shamin Syed, who are both from Pakistan. Adnan has an older brother named Tanveer Syed and a younger brother named Yusuf Syed.

Adnan was 7 months younger than Hae Min Lee (이해민), who was originally from South Korea. He dated her while they were classmates at Woodlawn High School in Baltimore.

Both Adnan and Lee were popular students when they attended Woodland High School. Here are 13 more things about him:

1. In 1998, he was the prom king at Woodlawn High School.
2. He is accused of murdering Lee, who went missing on January 13, 1999 and found dead on February 9, 1999. On February 28, 1999, he was arrested and charged with first-degree murder. He was later charged with kidnapping, robbery and false imprisonment.
3. On December 8, 1999, his trial presided over by Judge William Quarles started in Baltimore City Circuit Court. On December 14, 1999, it ended in a mistrial after Quarles called his lawyer Cristina Gutierrez a liar loud enough for the jurors to hear. He later replaced Gutierrez with Charles Dorsey. Gutierrez was disbarred in 2001 and she died in 2004.
4. On January 21, 2000, his second trial presided over by Judge Wanda Heard started. On February 25, 2000, he was convicted of murder and all related crimes in the death of Lee. On June 6, 2000, Heard sentenced him to life plus 30 years in prison.
5. In 2003, the Maryland Court of Special Appeals affirmed his conviction.
6. In 2010, he filed a motion for post-conviction relief, asserting that Gutierrez had provided ineffective representation in several areas, including her failure to call Asia McClain as an alibi witness.
7. On January 9, 2014, Judge Martin Welch of Baltimore City Circuit Court denied his motion for post-conviction relief. He filed a motion for a leave to appeal to the Maryland Court of Special Appeals, which was supplemented with an affidavit from McClain on January 20, 2015 and granted on February 6, 2015.
8. On October 3, 2014, his conviction and Lee’s murder became the subject of “Serial,” a podcast developed by journalist Sarah Koenig and the producers of the public radio show “This American Life“.
9. On June 30, 2016, Welch threw out his conviction and granted him a new trial based on Gutierrez’s failure to use the disclaimer to adequately challenge the cellphone records of the state of Maryland, which subsequently appealed.
10. In 2018, he turned down a plea bargain that would have allowed a sentence reduction. 
11. On March 8, 2019, the Maryland Court of Appeals reversed and reinstated his conviction. On March 10, 2019, the documentary series “The Case Against Adnan Syed” premiered on HBO. On August 19, 2019, he petitioned the U.S. Supreme Court to hear his case. On November 25, 2019, the U.S. Supreme Court denied his petition without comment.
12. On September 15, 2022, Marilyn Mosby, Maryland’s attorney for Baltimore City, filed a motion to vacate his conviction, which was granted by Judge Melissa Phinn of Baltimore City Circuit Court on September 19, 2022. On October 11, 2022, prosecutors in Baltimore dismissed the charges against him.
13. He was 41 years old when a Maryland appellate court reinstated his conviction on March 28, 2023.