MIAMI—President Trump launched an effort to expand the conservative Christian support that helped power him to the White House from a Miami megachurch, making an appeal to Hispanic evangelicals.

At King Jesus International Ministry, Mr. Trump unveiled an “Evangelicals for Trump” coalition Friday. The event had the hallmarks of a campaign rally, packed with attendees in Trump garb, but also opened with religious music and prayer. Evangelical leaders in attendance included Tony Perkins, president of the Family Research Council, and Paula White, who works for the White House as an adviser to the Faith and Opportunity Initiative, as well as King Jesus Ministry’s pastor, Guillermo Maldonado.

“In 2016, evangelical Christians helped us...they went out and they worked so hard and they produced numbers like they never produced before,” Mr. Trump said. “We’re going to blow those numbers away in 2020.”

Campaign spokeswoman Kayleigh McEnany said the coalition aims to sign up thousands of members and would seek to “maintain the extraordinary support of the evangelical community but also to expand it.”

She added: “We definitely see we can make inroads with black and Hispanic evangelicals,” arguing that the president’s record on religious issues would be appealing to those voters.