Polls closed at 5 p.m. local time, and though Turkey does not have exit polls, the Supreme Electoral Council said it hoped to announce preliminary results before midnight.
Here are five reasons why Erdogan, who could theoretically stay in power until 2028, dominated these elections and may continue to dominate Turkish politics for years to come.
Ignacio Sanchez Amor, the head of the ODIHR's short-term observer mission for the elections, said opposition parties were denied equal conditions for campaigning and Erdogan and his ruling party enjoyed undue advantages, including in the media.
Erdogan, the most popular but also divisive leader in modern Turkish history, moved the elections forward from November 2019, arguing the new powers would better enable him to tackle the nation's mounting economic problems - the lira has lost 20 percent against the dollar this year - and deal with Kurdish rebels in southeast Turkey and in neighboring Iraq and Syria. Nonetheless, citizens demonstrated their commitment to democracy by participating in large numbers in campaign rallies and on election day, the observers said.
In the parliamentary contest, the Islamist-rooted AK Party had 43% and its MHP ally 11%, based on 98% of votes counted, broadcasters said.
Erdogan, who has been in power since 2003, has faced a more robust, united opposition than ever before.
Results released by Turkey's state-run Anadolu news agency based on data from the YSK also gave Erdogan a clear majority of votes.
The BBC says that in winning the election, Erdogan will "assume major new powers under Turkey's new constitution". "We have now fully adopted a regime of one-man rule", he told journalists at a post-election news conference.
Erdogan and the AK Party claimed victory in Sunday's presidential and parliamentary elections after defeating a revitalised opposition that had gained considerable momentum recently and looked capable of staging an upset.
Ince's opposition Republican People's Party (CHP) had 23 percent.
One of the big takeaways from the election is that the Kurdish Peoples' Democratic Party (HDP) passed the 10% threshold to enter parliament. The opposition nationalist Iyi (Good) party had 10 percent, according to state media.
Speaking in televised remarks from Istanbul, he said "the nation has entrusted to me the responsibility of the presidency and the executive duty".
"Turkey has given a lesson in democracy to the entire world", he added, pointing to a turnout of 88 percent.
Why did Erdogan hold elections early?
Having defeated the twin threats of a reinvigorated opposition and a weakened currency, Erdogan addressed cheering supporters in the capital, Ankara, saying the victor of the election was democracy, the national will and the nation itself. "With the presidential system, Turkey is seriously raising the bar, rising above the level of contemporary civilisations". Erdogan's foes accuse him of dismantling Ataturk's secular legacy by bringing religion back into public life.
The expanded authority of the office is the result of constitutional changes narrowly approved in a referendum previous year, which will afford Erdogan autonomy to directly appoint top public officials. While Erdogan's opponents said they would send refugees back to their country, Erdogan did not.
CHP party spokesman Bulent Tezcan, however, challenged the election results provided by the Anadolu Agency, saying the party would continue working through the night to monitor the counting of the votes.