The development came days after Mr Dhindsa and Sukhbir Badal held talks to finalise the reunion.
Ahead of Lok Sabha polls, former Union minister Sukhdev Singh Dhindsa Tuesday merged his Shiromani Akali Dal (Sanyukt) with the Sukhbir Singh Badal-led Shiromani Akali Dal.
The development came days after Dhindsa and Badal held talks to finalise the reunion.
Later, speaking to reporters here, Mr Dhindsa termed the merger as "a joint responsibility to bring Punjab back on track", while Mr Badal called it a "merger of two families".
Mr Dhindsa and his son and former finance minister Parminder Singh Dhindsa were expelled from the SAD in February 2020 for alleged anti-party activities, after which they floated the SAD (Sanyukt).
The talks for the reunion commenced in December last year when Badal sought an apology for the sacrilege incidents that took place during the Akali regime in 2015.
He had then appealed to dissident Akali leaders to shun their differences to come under one flag.
The merger came amid the buzz over the SAD-BJP reunion. The Akalis had quit the NDA in 2020 over the now-repealed farm laws.
The SAD (Sanyukt) had contested the 2022 Punjab Assembly polls in alliance with the BJP.
After the merger, Dhindsa said, "There was an overwhelming feeling among our leaders and workers to merge with the SAD to effect unity in the 'Panth'." The former Rajya Sabha member said the entire party felt that Sukhbir Singh Badal expressed heartfelt remorse for the cases of sacrilege which occurred in 2015.
"Accordingly, I called a meeting of the party's district presidents yesterday and they gave the go-ahead for the merger," he said.
"Present times demand that the SAD should be strong, which will make the 'panth' strong. Sukhbir Singh Badal is like my son," said Dhindsa.
"You are seeing Punjab's situation today, the situation of law and order. It is our responsibility that we collectively raise our voice," he said.
"The day Sukhbir Badal apologised before Akal Takht, we formed a five-member committee and took feedback from people across Punjab and the majority suggested that we should unite. I spoke with my party's senior leaders and they authorised that whatever decision I take will be acceptable to them," said Dhindsa.
Earlier, SAD president Badal visited Mr Dhindsa's residence here along with senior leaders of the party including those from Sangrur district.
Addressing the media at Mr Dhindsa's residence, Mr Badal termed the merger as a "merger of two families".
He also appealed to Dhindsa to take on responsibility as patron of the SAD since he was the senior most Akali leader after the demise of former chief minister Parkash Singh Badal.
He said Dhindsa, along with senior leaders like Balwinder Singh Bhundar, had built the SAD along with Parkash Singh Badal at "great personal cost".
He also assured all the leaders of the SAD (Sanyukt) who joined the SAD of full respect and honour.
Mr Badal also welcomed Mr Dhindsa's son Parminder Dhindsa into the party fold on the occasion while appreciating the leader's contribution towards Punjab.
He also issued a clarion appeal to all Akali leaders who left the party on one pretext or another, to rejoin it saying "The SAD alone is capable of safeguarding the aspirations of Punjabis".
During this appeal, the SAD president even joined his hands and said "I am ready to apologise to everyone".
To a media query, Mr Badal reiterated, "I appeal to Bibi Jagri Kaur ji with folded hands to return to the party fold." "If Punjab is to be saved, strengthen the SAD. The only party which can sacrifice anything for the people of Punjab," said Badal.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)