Joe Xuereb, 27, was arrested after two women were left critically injured in Adderley Gardens, Eltham, southeast London.
Police believe a hammer recovered from the scene “may have been used” to carry out the “horrific attack” on Sunday.
Xuereb was arrested at 7.35pm in Old Farm Avenue, Sidcup, roughly two miles from where the women were allegedly targeted.
The Met Police has said the suspect was detained as a direct result of a media appeal to find him.
The force said it received “a number of calls” and that one member of the public followed the Xuereb in her car until police had detained him.
A taser was deployed during his arrest but was not used.
Officers were called to Adderley Gardens at 12.10pm, where neighbours described hearing a scream and later seeing the pavement covered in blood.
An air ambulance was sent to the scene and officers later revealed the women were “fighting for their lives”.
Both women, aged 30 and 64, were taken to south London hospitals where they remain in critical conditions.
A crime scene is still in place as police enquiries continue.
Detective Superintendent Jane Corrigan said: “I would like to pass my thanks to the public and the media for all their support.
“I am extremely proud of my colleagues and the community, who have all done so much to bring this part of the investigation to a safe resolution.
“It shows what can be achieved when we all work together.”