In a shake-up of the Maryland lobbying corps, Timothy A. Perry, last year’s top earner in Annapolis, announced the formation of a new firm Monday with former Prince George’s County delegate Justin D. Ross and Josh White, a former campaign manager to Gov. Martin O’Malley (D).

Rounding out the Annapolis-based Perry, White, Ross & Jacobson will be Jonas Jacobson, a former deputy secretary at Maryland’s Department of the Environment, the firm said.

Perry, a former chief of staff to Senate President Thomas V. Mike Miller Jr. (D-Calvert), reported $1.3 million in earnings for the year ending in October 2012, more than any other Annapolis lobbyist.

Both Perry and Jacobson are leaving Gordon, Feinblatt, Rothman, Hoffberger & Hollander, a firm that collectively ranked No. 3 in the most recent annual lobbyist listings compiled by the State Ethics Commission.

White, whose résumé also includes stints with Miller, the O’Malley governor’s office and the Maryland Democratic Party, is departing Rifkin, Livingston, Levitan & Silver, the No. 1 firm in the most recent annual rankings.

Ross (D) announced his retirement from the House of Delegates last fall after quickly rising to the position of chief deputy majority whip.

The title understated the importance of the role he had played in helping round up votes for key pieces of legislation, including the legalization of same-sex marriage and expansion of gambling.

By the time of his departure, Ross had become one of the most trusted lieutenants of House Speaker Michael E. Busch (D-Anne Arundel). When he left, Ross said he wanted to spend more time with his four young children and concentrate on building his private-sector business career.

There has been a recent wave of senior staffers in Annapolis leaving their government jobs for more lucrative lobbying posts. But the trend had been joining more established firms, which also include Alexander & Cleaver and Manis Canning & Associates.