Assalamu Alaikum,
In our masjid, a person (not the Imam) performs Salah in Jamah and then leads the prayer for late comers for Farz Salah. This happens specifically during Salath-al-Asr.
Please let me know if this act is acceptable in the light of Quraan and Sunnah?
Jazakallahu Khair

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

It is proven in the Sunnah that it is permissible for a person who performs a supererogatory prayer to lead a person who performs an obligatory prayer as in the narration of Mu’aath when he used to perform ‘Isha prayer with the Prophet then he goes back to his people and leads them in ‘Isha prayer again.

However, the person whom you mentioned in the question that he performs the prayer again as a supererogatory prayer after the ‘Asr prayer, then this is disliked because performing supererogatory prayers after Fajr and ‘Asr is disliked according to the view of the majority of the scholars . That is because Abu Sa’eed Al-Khudri narrated that the Prophet said: “There is no prayer after ‘Asr until the sun sets, and there is no prayer after Fajr until the sun rises.” [Al-Bukhari and Muslim]

Allaah Knows best.