President Trump’s had nearly three and a half years to build his 2020 reelection campaign juggernaut.

That’s not the case for former Vice President Joe Biden, who declared his candidacy for the White House in April of last year. And Biden’s team was smaller in size than some of his rivals in the Democratic presidential primaries. But since becoming his party’s presumptive presidential nominee in April, the former vice president’s been quickly building his staff as he challenges Trump in November’s general election and faces off against a campaign that enjoys large advantages in size, strength and funding.

Here's a look at some of the leading players in Biden’s presidential campaign team.

Jennifer O’Malley Dillon – campaign manager

(Photo Courtesy: Precision Strategies)

Biden named O’Malley Dillon as campaign manager in early March, as the former vice president was sweeping through the primary calendar on his way to becoming the presumptive nominee. She also took over running the campaign as the coronavirus pandemic shut down the country, forcing Biden’s team to transition to virtual campaigning and fundraising.

The longtime Democratic operative is a veteran of numerous presidential campaigns, starting with then-Sen. John Edwards' 2004 White House bid. She served as Edwards’ Iowa caucus state director during his second run in 2008 before joining then-Sen. Barack Obama’s campaign as battleground states director in the general election. She was the Democratic National Committee’s executive director before heading back on the presidential campaign trail as deputy campaign manager for President Obama’s 2012 reelection.

O’Malley Dillon co-founded Precision Strategies in 2013 and was the lead consultant to Canadian Liberal Party leader Justin Trudeau ahead of his 2015 victory to become that country’s prime minister. Following the divisiveness between the Hillary Clinton and Bernie Sanders camps in the 2016 election, she was named chair of the DNC’s Unity Reform Commission.

Last year O’Malley Dillon served as campaign manager for former Rep. Beto O’Rourke’s presidential bid. After a meteoric rise and a slow burnout, O’Rourke suspended his campaign at the beginning of November.

O’Malley Dillon joined the Biden campaign in February, assisting in the Nevada caucus effort, where Biden – after disappointing showings in the Iowa caucuses and New Hampshire primary – started to turn things around with a distant but second-place finish behind Sanders.

Kate Bedingfield – deputy campaign manager/communications director

Bedingfield, like O’Malley Dillion, is a veteran of the Edwards 2008 campaign, where she served as a spokeswoman. In the general election, she ran communications for Jeanne Shaheen’s successful challenge against Republican Sen. John E. Sununu of New Hampshire.

Bedingfield served in the Obama White House as the deputy director of media affairs, the director of response, and an associate communications director, managing communications involving the administration's agenda. After a couple of years as vice president of corporate communications at the Motion Pictures Association of America, she returned to the White House as then-Vice President Biden’s communication director in the final year and a half of the Obama administration.

Bedingfield – who remained close with Biden after he left office – joined his campaign at the outset as deputy campaign manager and communications director.

Greg Schultz – former campaign manager/organization outreach to DNC and states

Schultz managed numerous local and statewide campaigns in Ohio before joining Hillary Clinton’s 2008 presidential campaign as the state’s political director. In the general election, he served as Obama’s Ohio deputy political director. He worked as Obama’s Ohio state director for the president’s 2012 reelection.

For the four years of Obama’s second term, Schultz served as a senior adviser for the vice president, and was executive director of Biden’s American Possibilities PAC from 2017 until taking over as Biden’s campaign manager when the team formed in April of last year.

After being succeeded as campaign manager by O’Malley Dillon in the March reorganization, Schultz now serves as a general election strategist, working to align and execute planning among the campaign, the Democratic National Committee, the Democratic state parties and other important stakeholders.

Symone Sanders – senior adviser

NEW ORLEANS, LA - JULY 06: Symone Sanders attends the 2018 Essence Festival presented by Coca-Cola at Ernest N. Morial Convention Center on July 6, 2018 in New Orleans, Louisiana. (Photo by Paras Griffin/Getty Images for Essence)

Sanders got a taste of politics at an early age, introducing former President Bill Clinton at an event in her native Nebraska when she was 16. She worked for Public Citizen – the outside organization founded by Ralph Nader. In July 2015, she joined Sen. Bernie Sanders' presidential campaign as national press secretary.

Sanders worked for Priorities USA – the flagship pro-Democratic super PAC – after the 2016 election. She joined the Biden campaign when it formed last year, and serves as a senior adviser and a leading cable TV surrogate for the former vice president.

Rob Flaherty – digital director

Flaherty’s known as a digital guru in Democratic circles. After steering the digital efforts for Terry McAuliffe’s successful 2013 run for Virginia governor, he served as director of digital media for the Democratic National Committee for a year and a half. He was deputy digital communications director for Hillary Clinton’s 2016 presidential campaign.

Flaherty worked as creative director for the Priorities USA super PAC for two years before joining former Rep. Beto O’Rourke’s presidential campaign in the spring of last year. After O’Rourke ended his bid, the Biden campaign hired him as digital director last December.

With the coronavirus grounding in-person campaigning and transferring all voter outreach and fundraising to the virtual online world, Flaherty’s more in demand than ever as the Biden campaign challenges a Trump campaign that started the general election with a huge digital advantage.