Police said the man, Lee Byer of Allenby Avenue UB12, will appear at Willesden Magistrates' Court in London today.
The family of Mr O'Halloran have been informed of the arrest, and have asked for their privacy to be respected at this time.
Mr O'Halloran, who used a mobility scooter, was originally from Ennistymon in Co Clare, and lived in the Greenford area of west London.
Police officers were called to Cayton Road, in Greenford, west London, on Tuesday to reports of a stabbing and 87-year-old Mr O'Halloran was declared dead at the scene.
He was said to be known locally for busking outside Greenford Station.
Members of the public are reminded that proceedings are now active and to refrain from sharing or publishing anything that may create a substantial risk of serious prejuudice that could undermine legal proceedings.
Anyone with footage of the incident is asked to upload it using this online form: Public Portal (mipp.police.uk)
If you have any other information about the murder, please call the incident room on 020 8358 0300 quoting 4691/16AUG.