June 3 (Reuters) - Alphabet's Google has hired

Donald Verrilli Jr, the U.S. solicitor general during the Barack

Obama administration, to appeal a judge's ruling that the tech

titan has an unlawful monopoly in online search, Google

confirmed on Tuesday.

Verrilli's hire is a key first step in Google's legal fight

to undo the ruling, which it has said could pose a threat to its

business.

U.S. District Judge Amit Mehta last year ruled Google holds

an unlawful monopoly in online search and related advertising,

and is considering proposals to make the tech titan sell off its

popular Chrome browser, or share data that CEO Sundar Pichai

says would allow competitors reverse engineer its search engine.

Google has argued the DOJ failed to prove that competition

was harmed by its exclusive agreements with device makers such

as Apple to preload Google as the default search engine on new

devices. The company has recently begun loosening its agreements

to allow partners including Samsung to load rival apps.

Verrilli, who as solicitor general was the Obama White

House's top Supreme Court advocate, is known for his work

successfully defending the Democratic president's signature

domestic healthcare law.

He will represent Google in its planned appeal to the U.S.

Court of Appeals for the D.C. Circuit, where

Democratic-appointed judges outnumber Republican ones 9 to 6.

Verrilli is separately the lead lawyer for law firm Susman

Godfrey in its lawsuit against the Trump administration over an

executive order that restricted its business. A judge in April

blocked key provisions of the order.

Verrilli is representing hundreds of other firms that filed

a court brief denouncing Republican President Donald Trump's

attacks on prominent law firms. He is also representing U.S.

Copyright Office Director Shira Perlmutter in a lawsuit

challenging her firing, and the National Endowment for Democracy

in a case accusing the Trump administration of illegally

withholding funds.

Verrilli's firm Munger Tolles has represented Google in

other lawsuits. The firm, whose founders include the late

Charlie Munger, has counted Berkshire Hathaway and Bank of

America as some of its other clients.