[1] Before representing his hometown of Longmeadow, Massachusetts, and neighboring communities in the Greater-Springfield area, he worked as a White House aide during the Obama administration.

He proposed and passed the Student Loan Borrower Bill of Rights as well as provisions for job training, tourism and the arts, substance abuse treatment, and environmental issues, among others.

[13][14] Lesser created a luggage-management system that earned him the trust of the campaign team, the traveling press, and his future boss, Obama advisor David Axelrod.

"[4][16] When the campaign ended, the Senior Advisor to President Obama, David Axelrod, tapped Lesser to serve as his Special Assistant.

[27][28] On February 3, 2014, The Republican newspaper reported that Lesser was considering a bid for the First Hampden & Hampshire seat in the Massachusetts State Senate that was recently vacated by Sen. Gale Candaras.

[31] On November 4, Lesser defeated Republican Debra Boronski and America First candidate Mike Franco to win the State Senate seat.

[42] Lesser believes that a high-speed rail line between Pittsfield and Boston would increase employment and boost the economy in Western Massachusetts.

[43] In his first month in office, Lesser filed a bill that would require a report of the costs and benefits of building higher-speed rail across the state.

Congressman Richard Neal, who currently chairs the powerful House Ways & Means Committee, noted that the "$66 billion that Amtrak will receive has the potential to be transformative nationwide but also right here in western and central Massachusetts.

[51] After the heroin epidemic resulted in 185 deaths in the first four months of 2014, Lesser created and published a four-point plan with concrete steps to address addiction.

Promoting the skills needed to critically analyze written and digital sources, Lesser said that, "Young people can, and must be, part of the solution to our most pressing challenges.

"[59] The bill also directed the Massachusetts Secretary of State to establish a non-partisan high school voter challenge program to encourage eligible students to register or pre-register to vote.

In 2019, Lesser said, "We need to build solar panels, wind turbines, and other pieces of equipment to help propel us forward to a high-tech economy.

"[66] Lesser is the co-chair of the 17-member Future of Work Commission that is developing a report on the "impact of automation, artificial intelligence, global trade," and other economic trends affecting drivers, musicians, and gig workers.

"[67] Lesser is also the co-chair of the Future of Work Initiative at NewDEAL, a national network of pro-growth, progressive state and local elected officials.

[68] Lesser has also proposed a remote worker relocation program, which would pay $10,000 over two years to employees that could move to western Massachusetts to work from home.

The increases come as the country and local communities in Massachusetts face more frequent incidents of hate targeting LGBTQ+, Black, Jewish, Asian, and Muslim groups.

"[73] To protect civil liberties, Lesser has proposed a bill requiring law enforcement to obtain a warrant before accessing data collected on drivers on the Mass Pike.

In April 2021, the Massachusetts Department of Environmental Protection announced that they would revoke the project permit to build the biomass power plant.

In May 2014, Lesser published an opinion piece in the Springfield Republican detailing a plan to support the increasing population of adults over 65 in Western Massachusetts.

[77] Since 2017, Lesser has hosted an annual "Thrive After 55" Wellness Fair where participating organizations answer questions and offer information about their resources to local seniors.

[78] During the coronavirus pandemic, the fair shifted online, offering virtual programming on financial security, identity theft, healthcare, and wellness.

[83] Eventually, Lesser questioned the director of the Merit Rating Board, Thomas Bowes, who was most directly responsible for processing these notifications.

“And for those with limited ability to navigate the internet, there is no access to appointment booking at all.”[89] As the rollout continued, long lines in cold weather prevented many Massachusetts residents from receiving the vaccine.

That’s a long time to wait in line and stand in 27-degree temperatures.”[90] Lesser requested that Baker appear before the legislature's COVID-19 oversight committee to answer questions.

[92][93] Following Baker's appearance before Lesser and the committee, the administration fixed the broken website, streamlined the system to book appointments, and signed new contracts to ensure that the rollout continued in a safe and efficient manner.

"[94] Staffing shortages led the facility to consolidate two dementia wards with infected veterans and healthy residents, increasing the risk of contracting the virus.

"Given the importance of empowering voters to believe every vote counts in a presidential election, the repeal of the Electoral College merits a thorough discussion and examination.

He is the co-chair of the Future of Work Initiative at NewDEAL, a national network of pro-growth, progressive state and local elected officials.

[64] Lesser has taught workshops on campaigns, elections, and public policy at Harvard's Kennedy School of Government and a class on millennial leadership in local and state politics at the University of Massachusetts Amherst.