The third-floor hallway outside the Massachusetts House of Representatives is a waiting area outside a delivery room. Inside are the people doing the work, and outside are those hoping for happy news.

Expectants stand in pinstripes and pantsuits, with skirts and throbbing BlackBerrys, conducting casual asides that look like grave discussions and serious policy disagreements that look like back-slapping.

If one of the choices relates to a matter of interest to nurses - or construction workers or casino interests or substance abuse counselors or police unions - there is a better-than-even chance that one of the individuals tarrying professionally outside the chamber will find himself or herself discussing the matter with Martin Walsh, Democrat of Dorchester, the 11-year state representative who has gone to bat for just about all of them.

Tim Sullivan, political coordinator of the state AFL-CIO, called Walsh's "sincere ferociousness" a distinguishing trait.

"Whether we ask him to work on our behalf or to defeat a bill, he's the go-to guy, whether his name's on top of the bill or not," Sullivan said.

This caseload does not always endear Walsh to the House leadership. While he clung to a vice-chairmanship in 2005, as House Speaker Salvatore DiMasi consigned several members who had opposed his speakership to legislative nowheresville, Walsh has since bear-baited the speaker on a passel of bills. Last year, at the beginning of the two-year legislative cycle, DiMasi booted Walsh and South Boston Rep. Brian Wallace, another substance-abuse funding crusader, from the Mental Health and Substance Abuse Committee. The pair fussed, and DiMasi brought them back on board several weeks later.

When a reporter suggested that it seemed he and DiMasi retained a friendly relationship, Walsh elaborated: "Very cordial."

Out of favor with the House leadership - he has a vice-chairmanship on the small-bore Municipalities and Regional Government Committee - Walsh has nonetheless found a way, colleagues say, to press his agenda without entirely capsizing the delicate ship that legislating can often be.

"It's worked for him. We know the issues that Marty cares about," said Rep. Marie St. Fleur, Walsh's fellow Dorchester Democrat.

Vice-chair of the powerful Ways and Means Committee, St. Fleur is in good with DiMasi, unlike Walsh. Her agenda is more likely to be taken care of within the normal course of business, not often requiring her to take a campaign public when she can press it quietly. Still, she says she admires Walsh's technique.

"He's very good at being very public, but he also knows how to go inside and work quietly with people," St. Fleur said last week. She added, "There are different ways of getting things done in this building."

Walsh noted, "As long as you do your job and show up every day, they respect you for that … It's easier the other way, but you learn more this way."

A passion for "real-life" recovery

The Interim House honors Walsh this Thursday with one of its three inaugural Yvonne Linehan Awards for Public Service in Substance Abuse Treatment, a nod to Walsh's focus in the field. Gov. Deval Patrick is expected on hand for "Raise the Roof II" event at Florian Hall, and to present Walsh's award.

Other recipients include Ben Wade, and Interim House graduate and now a staff counselor, and Howard Cutler, a CPA who has served pro bono as the facility's accountant and financial adviser since it was founded in 1972.

The benefit auctions, with proceeds going to renovations on the Fields Corner building, feature tickets to Theo Epstein's box at Fenway for a Sox game, a guided tour of the White House with Congressman Stephen Lynch, concert and theater tickets, museum passes, yoga classes and more. The Interim House treats 18 men at a time in six month, Alcoholics Anonymous-based programs.

For Walsh, himself 13 years without a drink, it's gone beyond a priority to a lifestyle. A Saturday afternoon finds him on Long Island for a 40-years-sober AA member. He's counting on the day when he gets a call from a longtime friend of his - whose wife has done time, their kids taken from them - asking him to help him find sobriety. "If he doesn't die, it'll come."

In the neighborhood, Walsh teams with longtime Savin Hill dweller Danny Ryan, offering informal counseling or literally driving addicts to recovery facilities.

"People know they can ask us and it's not just calling a politician and hoping for something," Walsh said.

It's a passion he brings to Beacon Hill. When he arrived in the House in 1997 after winning a spicy special election to succeed James Brett, Walsh learned from the late Rep. Kevin Fitzgerald, then the reigning champ of securing funding for detox beds and counseling. Now, Walsh has joined a small coterie of mostly urban lawmakers - among them Wallace, Rep. Ruth Balser, and Senator Steven Tolman - for whom substance abuse policy is a career calling card.

"Substance abuse is number one - not even the funding," he said. "If people can take one person to detox, and turn that one life around, just one, they've changed the generational outcome for that family."

During this year's volatile House budget debate, the oft-raucous chamber hushed for Walsh's emotional account of the one time in his House career he'd missed a phone call from a constituent looking for a detox bed. "I missed that phone call and I called the person back who called me and I left a message for them," Walsh told his silent colleagues.

"On the Monday morning, a call came to my office to let me know that they no longer needed my services because the young man that they were calling for passed away of a heroin overdose. This is real-life stuff," he said.

Later, asked about the speech during an interview on the deck of his Tuttle Street home over coffee and mini-cigars, Walsh said, "It might've been his time to go. But I wish I had been able to get that phone call. Because you never know."

The loyal opposition

Walsh praised the current House leadership for its willingness to bankroll the types of programs he champions. But he is one of its most energetic thorns on another front: Walsh is one of the leading House members touting House Majority Leader John Rogers's not-so-quiet hopes of becoming the next speaker of the House, once the current inhabitant of that post, DiMasi, leaves.

Walsh is one of a number of Rogers backers, many of them Irish-Americans, relegated to virtual legislative oblivion when DiMasi took over for Tom Finneran in 2004. That gang is thirsting to be back in power, hoping Rogers can outwork Ways and Means chairman Robert DeLeo for the spot.

While DiMasi recently appeared to back off a threat to punish House members who worked actively to scoop up votes for the speakers-in-waiting, the capitol still buzzes with speculation about when DiMasi, under a cloud of ethical questions regarding friends who fared well in the legislative corridors, could go and who might succeed him.

"I haven't noticed anything different" about the way he's been treated since the maneuvering began, Walsh said. "Bob DeLeo's been good to me, as the chairman of Ways and Means. I don't get everything I want, but I didn't get everything I wanted under Tommy Finneran, either. I'm sure behind closed doors they're upset with me."

Open to press scrutiny because of some of the most active members' indiscretions, the game - replete with scoresheets and team captains - has destabilized the House under DiMasi.

"It's different this time," Walsh said. "It never got to this level this early. And we don't know if it's early or late … It could be healthy for the chamber if we knew there was a date the speaker was going to leave."

Just as there's been no movement atop the House chamber since Finneran left, Walsh has also watched in relative dismay as the offices above him in the dotted line of succession have also seen little turnover. If anything, it appears to have cooled the impatience that in earlier years led Walsh to consider, with some rashness, a range of offices.

If not a helping of electoral reality, Walsh's focus now seems to reflect a political maturity, a measure of patience about his career path. At 41, he exudes less urgency now than he did at 35. Of course, a mayoralty or a Congressional seat or a state Senate post aren't ever too far from his thinking.

"At some point, if the opportunity comes, maybe I'll have the chance to run for higher office. But one thing you learn in politics is you just don't know what's going to happen," he said.

"Politics is funny. It's like recovery: a day at a time."