Andy Puzder, former CKE Restaurants CEO, told CNBC on Tuesday he's used to being attacked for conservative economic positions, but he's seen nothing like the vitriol he experienced from the media as President Donald Trump's first Labor secretary nominee.

After several delays of his confirmation hearing — in part over financial disclosure and ethics paperwork — and not enough GOP support, Puzder bowed out on Feb. 15.

Puzder said he couldn't even tweet during the vetting — adding he would have liked to defend himself against accusations that were being circulated at the time, including alleged wage violations at CKE locations and decades-old abuse allegations from his ex-wife.

"It was tough. When I became the focus of the efforts to try and wipe somebody out, it became very intense," he said on "Squawk Box." "It's hard if you can't go on and defend yourself."

In making his case for confirmation, Puzder said he had "some good meetings with Democratic senators who "probably would have supported" him.

"One of the things that came out talking to senators is that Democrats really thought they were going to win," he continued. "They thought they were doing to have the presidency into the foreseeable future."

Late last month, Puzder decided to step down as chief executive CKE, the parent company of fast food chains Hardee's and Carl's Jr. His last day on the job he held since 2000 was Monday.

The president's second choice for Labor secretary, Alex Acosta, received Senate committee approval at the end of last month. The nomination of Acosta, a former Justice official, is expected to soon go before the full Senate. If confirmed, Acosta would be the first Hispanic member of Trump's Cabinet.