John Sheridan and the work before the title

John Sheridan gave away the job in four words. At an investor conference in March 2026, an analyst introduced Susan Morrison, Tandem’s chief administrative officer, as a wearer of many hats. Sheridan supplied the shorter version: “She runs the company.” Morrison’s answer was one word: “Facts.” For a moment, the chief executive’s role required no solemn explanation. The people beside him had work to do, and he was happy to say so.

It is a useful opening to a career that can otherwise look like a procession of executive titles. Sheridan has spent decades close to operations, the unromantic business of getting an organization to deliver what it says it will. His route to Tandem’s top job included nearly six years inside the company. By the time his title changed, there was already a long working relationship behind it.

The joke suggests a willingness to share the stage. The career supplies a more substantial question: how does an executive learn to run the whole business? In Sheridan’s case, the answer begins well before the CEO appointment.

Nearly six years inside

He arrived at Tandem in April 2013 as executive vice president and chief operating officer. His appointment as president and chief executive took effect on March 1, 2019. In June, he also joined the board. Those dates describe three different responsibilities: running operations, leading the company, and participating in its governance.

Nearly six years is a considerable introduction to an employer. An internal successor has a particular advantage: the company’s history includes decisions he helped make. He inherits relationships as well as responsibilities. There is less room for the flattering fiction that all previous difficulties were somebody else’s doing.

That is an interpretation of the succession, rather than a claim about Sheridan’s private thoughts. The documented point is simpler. He had been responsible for Tandem’s operations for years when the board chose him for the larger role. The promotion extended an existing assignment.

A career with its sleeves rolled up

Sheridan’s education paired a bachelor’s degree in chemistry from the University of West Florida with an MBA from Boston University. His subsequent career repeatedly brought operations into the same job description as technical work. That combination is worth attending to. Companies need people who can discuss an invention and people who can organize its delivery; sometimes the responsibilities land on the same desk.

At Digirad, he served as vice president of operations from March 1998 to May 2002. At CardioNet, he became executive vice president of operations, serving from May 2002 to May 2004. The repeated word is doing useful work here. Operations is the connection between a company’s intentions and its daily output.

His remit at Volcano Corporation explicitly joined research and development with operations. He held the executive vice president role from November 2004 to March 2010. It placed work on future products alongside responsibility for the organization making them. The title itself captures a familiar tension: developing something new while ensuring the existing business still functions.

Then came a change of setting. From March 2012 to February 2013, Sheridan was chief operating officer at Rapiscan Systems, a supplier of security equipment and systems. Tandem followed in April. His route crossed industries while retaining an operational center of gravity. A production schedule, one suspects, has little patience for the glamour of its surroundings.

The business of handing over

The 2019 transition had another important feature. Kim Blickenstaff, Tandem’s outgoing chief executive, moved into a newly created executive chairman position. Sheridan took responsibility for leading the business while his predecessor continued with external and corporate strategy. The announcement described a division of responsibilities that preserved a working partnership.

Blickenstaff expressed confidence in Sheridan’s ability to advance day-to-day activities. Sheridan, in turn, publicly emphasized their collaborative relationship and his expectation that it would continue. Such language can sound ceremonial. Here, the arrangement gave it practical meaning: both executives remained involved, in different jobs.

For a successor, continuity carries obligations alongside benefits. The new leader has to use inherited knowledge without allowing familiarity to settle every question. For the predecessor, a changed role requires leaving room for someone else’s decisions. Those are the structural demands of the arrangement; the announcement made the handover visible.

In February 2023, Rebecca Robertson succeeded Blickenstaff as board chair. Sheridan’s public response thanked Blickenstaff for his contributions since 2007. Leadership continued to change around him. The company’s story involved a succession of people carrying different parts of the enterprise forward.

A colleague, remembered in detail

A smaller public gesture offers a more personal view. On LinkedIn, Sheridan recommended Tim Glynn, a colleague he said he had known for twenty years. They had worked together at Volcano and overlapped again while Sheridan was on Acutus Medical’s board. The recommendation explained the history behind the endorsement.

He praised Glynn’s communication, practical judgment, teamwork, and willingness to get the job done with integrity. These were Sheridan’s observations about somebody else. They also tell us which qualities he chose to put into a public professional recommendation. Technical and commercial experience appeared beside the experience of working with a person.

The gesture has a pleasant lack of ceremony. A former colleague needed a next opportunity; Sheridan put his name behind him. Seniority gives an executive a platform. In this instance, he used a little of it to direct attention toward someone else. The recommendation is a concrete act, small enough to understand without a management diagram.

Room for more than one winner

Sheridan’s public comments about competition reveal another aspect of his business thinking. Asked about rivals in January 2022, he said: “It’s not a zero-sum game.” He argued that market growth could create room for several companies to succeed. It was a statement about the opportunity he saw at that time.

The distinction matters to strategy. A business that expects growth from an expanding market must still win customers, but its reasoning includes people who have yet to enter the category. Competitors remain consequential. The available opportunity can also change. Sheridan’s argument allowed both ideas to occupy the same conversation.

“Ease of use is what drives adoption.”

John Sheridan, April 2025

In an April 2025 conversation with Bloomberg Intelligence, he returned to ease of use. That emphasis connects the executive’s operating responsibilities to the customer’s experience. A company can assemble considerable technical sophistication and still ask too much of the person using its work.

Simplicity, in this reading, becomes a business concern. The customer has a day to get through. Every confusing interaction makes a competing claim on that time. Sheridan’s repeated attention to convenience gives his public strategy a recognizable focus: the work should make sense from the other end of the transaction.

Accountability has a first person

His message in Tandem’s 2022 inclusion report brought responsibility closer to home. Sheridan described an effort that began with volunteers in 2020 and gained a formal company function in 2022. He tied a broader range of perspectives to creativity and productivity, and supported annual reporting so employees and outsiders could follow the work.

He also made the commitment personal: “I’m committed to holding myself and our leaders accountable for continuing down this path.” The first person matters. It places the chief executive within the group being assessed.

A public commitment establishes something people can return to. Its value depends on what follows, but the statement itself has a useful property: it can be compared with later decisions. For an operations executive, there is a familiar logic here. An intention becomes more demanding when somebody agrees to report on it.

The billion-dollar line, and the next line

Tandem reported worldwide sales of $1.015 billion for 2025. Sheridan was leading a business operating at a scale that gave the annual number an extra digit. The milestone belonged to the company and its workforce, with the chief executive answerable for what came next.

The next set of numbers makes the assignment clearer. For the second quarter of 2026, Tandem reported worldwide sales of $254.6 million, a gross margin of 57 percent, and a net loss of $21.2 million. Revenue had grown six percent from the same quarter a year earlier. Greater scale and a remaining loss appeared together.

Those measures describe different periods and different aspects of performance. They belong beside each other here because a leadership story needs room for both achievement and unfinished work. A sales milestone does not settle the economics of running the organization. The figures keep the continuing responsibility in view.

Sheridan’s career gives that responsibility a long prehistory. Operations at Digirad and CardioNet. Development and operations at Volcano. Security systems at Rapiscan. Almost six years as Tandem’s COO. The sequence shows how much of his working life preceded the title most readers now associate with him.

Return to the conference introduction and the colleague beside him. A company of this scale depends on people whose responsibilities cannot be compressed into one person’s biography. Sheridan’s joke acknowledged that in a few seconds. His longer assignment is to make the shared work add up. The title fits on one line. The work keeps filling the page.