(CNN) Kevin McAleenan, the acting secretary of homeland security since April and the fourth person to serve in that post since the Trump presidency began, submitted his resignation to the White House on Friday, President Donald Trump announced Friday.

"Kevin McAleenan has done an outstanding job as Acting Secretary of Homeland Security. We have worked well together with Border Crossings being way down. Kevin now, after many years in Government, wants to spend more time with his family and go to the private sector," Trump said. "Congratulations Kevin, on a job well done! I will be announcing the new Acting Secretary next week. Many wonderful candidates!"

A source familiar with McAleenan's thinking tells CNN that the acting secretary felt he had accomplished all he could given the political realities of today -- specifically the unlikelihood that any legislative deal on immigration will happen in an election year. Moreover, with the numbers of undocumented immigrants apprehended or turned away at the border coming down for the fourth consecutive month -- 52,546 in September, a 65% drop from May -- the lack of crisis is dissuading members of Congress to act and compromise. McAleenan also has two young daughters and a wife with whom he wants to spend more time.

The announcement has been planned for weeks, sources close to McAleenan say, and has nothing to do with the Ukraine scandal in which Trump and several other Cabinet officials are currently enmeshed.

A source close to the process told CNN that White House officials tried to talk McAleenan out of resigning.

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