His performance earned him a transfer to Sepahan Isfahan in 2013 and spent four years with Talaei Pooshan, which included a successful loan spell with Tractor in Tabriz.

[13] In his first season, under Croatian coach Zlatko Kranjčar, he formed a partnership in the heart of the Sepahan defensive with the captain Hadi Aghily.

[16] He was one of the best players under coach Amir Ghalenoei, the club reached the top of their group at the 2016 AFC Champions League, outperforming the Saudi giant Al-Hilal.

"[16][19] On 6 May 2017, it was confirmed that Khalilzadeh would join the Persian Gulf Pro League champions Persepolis on a two-year contract to play under Croatian coach Branko Ivanković.

Persepolis reached the semi-final for the first time in its history before FIFA imposed sanctions on the team's top scorer and the club.

The following year was the most successful in Persepolis history against all odds, the Reds finished runner-up in the 2018 AFC Champions League.

In the Round of 16 against Al-Sadd, the role and interventions of Khalilzadeh in the game were more influential, before Persepolis scored the winning goal in the 89th minute.

[39][40] On 25 October 2020, Al-Rayyan announced on the last day of the summer transfer window the signing of Khalilzadeh on a two-year contract a worth $700,000.

[49] After seven years of notable absence from the international side, during the time of Queiroz and Marc Wilmots,[50][51] Khalilzadeh was call-up by new coach Dragan Skočić in 2020 for a friendlies against Uzbekistan and Bosnia and Herzegovina,[52] and to help in a difficult situation, after the failure in the 2019 AFC Asian Cup and two consecutive defeats from Bahrain and Iraq in the second round of qualifiers for the 2022 FIFA World Cup.

[65][66] Khalilzadeh is the preferred defender for most coaches, especially the Croats Miroslav Blažević, Zlatko Kranjčar, Branko Ivanković and Dragan Skočić.

[11][18][66][67][68][16] Khalilzadeh was born in the small village of Gālesh Kolā in Bahnemir District, Babolsar County, Mazandaran Province, to a family working in agriculture and fish farming on the Caspian Sea.