On state TV, CHP leader Kemal Kilicdaroglu announced the CHP deputy Ince was their choice.
"On June 24, I will God willing be president by the wish of the people," said Ince.
He is known for being a solid and demonstrative public speaker.
"For eighty million people (Turkey's population)... I will be everyone's president. I will be an unbiased president," he said.
Ince, who turned 54 today, is from Yalova. The former physics teacher has been an MP since 2002.
"Muharrem Ince is the best candidate that CHP could select in terms of rallying the party base," Sinan Ulgen, chairman of the Centre for Economics and Foreign Policy and visiting scholar at Carnegie Europe, told AFP.
"He will be able to ensure a large turnout of the CHP electorate on election day."
Kilicdaroglu previously said he would not run in the June 24 election against Erdogan.
In CHP's 36th congress in February, Ince received 447 votes — second to Kilicdaroglu's 790.
The CHP is in an opposition coalition with the Iyi (Good) Party, the Islamist Saadet Party and the Democrat Party.
The pro-Kurdish HDP was not included in the coalition and has announced that charismatic former party co-leader Selahattin Demirtas and presidential candidate in 2014 will challenge Erdogan.
Demirtas is currently imprisoned because of remarks he made on the campaign trail during the previous election, running against Erdogan.
The elections will be held during an ongoing state of emergency that has been in place since the failed military coup in 2016.
