- "In a day, the Reach had lost its King, its ruling house and most of its army. Thankfully for everyone, my ancestor Harlen Tyrell had better sense. Until the Maesters sorted out the entail among Mern’s cousins, Harlen the steward was acting Lord of Highgarden. To ensure peace and life in the Reach he would yield the castle to Aegon. The other castles and families would then follow, as they had since the Dawn Age."
- ―Margaery Tyrell
Lord Harlen Tyrell was the steward of Highgarden during the reign of King Mern IX of the Reach. After the death of his king in the Field of Fire, Harlen surrendered Highgarden to Aegon the Conqueror. Afterward, Aegon elevated Harlen to Lord Paramount of the Reach and Warden of the South and House Tyrell to the status of a Great House.
According to Olenna Tyrell, Harlen was like most Tyrell men and grew up banging steel too loudly for thought to penetrate, like his descendants Luthor, Mace, and Loras. She also implies that it was Harlen's wife who came up with the idea to surrender to Aegon and convinced Harlen to go along with it.
In the books
In the A Song of Ice and Fire novels, Harlen Tyrell's story is the same.
|Lord:||None, extinct||Heir:||None, extinct|
|Title(s):||Lord of Highgarden · Lord Paramount of the Reach · Warden of the South|
|Ancestors:||Garth Gardener · Harlen Tyrell · Lyonel Tyrell|
|Deceased members:||Luthor Tyrell · Mace Tyrell · Margaery Tyrell · Loras Tyrell · Olenna Tyrell · Tyrell lady · Alerie Tyrell|
|Household:||Mira Forrester · Sera Durwell|
|Overlord:||House Targaryen · House Baratheon of King's Landing (formerly) · House Gardener (formerly)|