Managing Sideways: The Leadership Skill No One Coaches You On
By Sophie Makonnen
We talk often about managing up. How to build trust with a supervisor, how to advocate for a project, how to be seen by the people who decide on promotions and mandates. We've explored this directly, including in Claiming Your Achievements: Becoming Your Own Best Advocate, on the work of making your contributions visible to the people above you.
We also talk about managing down, the discipline of leading a team well, setting clear expectations, and creating the conditions for people to do good work. From Doing to Leading looked closely at that shift, the moment expertise alone stops being enough and a different kind of leadership has to take over.
We've written about the relationships that extend beyond our immediate role too, including a practical look at how to build a network with intention rather than urgency.
Managing up, managing down, building a network outside our immediate role: these are the classics of leadership advice, the topics that get taught, coached, and written about. And for good reason, given that success still depends on the quality of our work, how we lead our teams, and how well we are known beyond our own desk.
But there is one dimension that gets far less attention, even though it shapes our influence and our reputation as much as the other two: our relationships with peers and colleagues, the people who sit beside us rather than above or below us. Managing horizontally, or what some call leading sideways, has no formal structure attached to it. No one reports to us there, and no one holds authority over us either. That absence of hierarchy is exactly why it is so often neglected, and exactly why it deserves a more intentional approach.
What Leading Sideways Actually Means
Thomas Barta and Patrick Barwise, writing in McKinsey Quarterly, surveyed more than 1,200 senior marketing executives and traced which leadership behaviors actually explained the differences in their outcomes. They looked at two outcomes separately: business impact, meaning contribution to revenue and growth, and career success, a self-rated measure of how far someone felt they had advanced. Managing a team well was the key differentiator for business results. But when it came to career success, the critical factor was something else: mobilizing the people around you, your boss, yes, but especially your colleagues, a behavior most leadership advice overlooks entirely. Not the team work.
We've already looked at the boss side of that equation, in When Influence Is Not Enough, where the limits of upward influence became the real subject. What we haven't looked at closely is the other half: the colleagues. The peers who owe you nothing, who have no obligation to follow your lead, and who, according to this research, matter just as much to how far your career actually goes.
Doing the work well and being seen to lead it are not the same accomplishment, and they don't run on the same fuel. You can produce excellent results through strong team management and still find that recognition and advancement depend on something else: whether the people beside you, not below you, experienced you as someone worth following. That is the part almost no one is formally prepared for.
So what does it actually mean to lead sideways, when the people involved don't report to you and never will? Barta and Barwise describe it in a specific way:
Leading from the front, with a story compelling enough to win over colleagues who owe you nothing, backed by a concrete plan that delivers something real. Do that well, and it builds on itself. Early support from a few colleagues becomes visible, that visibility draws more, and the initiative gains its own momentum, not because anyone was ordered to support it, but because they chose to. This is not networking. Networking is about staying connected and visible over time, and it matters, but it's different work.
Leading sideways is narrower and more demanding. It's the ability to get colleagues who owe you nothing to move with you on something specific, because the idea is worth their time and the plan is credible enough to act on. It's also not the same as being well-liked, or collegial, or easy to work with. Those things help, but they're not the mechanism. The mechanism is vision plus delivery, in a relationship where authority was never on the table to begin with.
“Who” This Actually Means
"Colleagues" is vague so it's worth being specific about who falls into this category, because for many readers it's a wider group than they'd assume.
It's the counterpart on another team whose work must connect to yours for either of you to deliver anything. It's the peer in a different unit or department you'll likely never supervise and who'll never supervise you, but whose support (or resistance) can quietly shape how your project moves. It's the colleague who joined around the same time you did, on a similar track, watching how you handle pressure. It's someone in a different function entirely, finance, communications, operations, whose cooperation you need but have no authority to require.
What connects all of them is the same thing that makes this dimension so easy to neglect: none of them owes you anything. No org chart obligates them to take your call, back your idea, or speak well of you when you're not in the room. Whatever influence you have with them, you built it, or you didn't.
Because these relationships don’t announce themselves as important for career progression, this is also where it can get blurry. Indeed, a supervisor's opinion of you obviously has consequences, while a colleague's opinion feels low-stakes until a decision needs cross-team buy-in or a stretch opportunity depends on who advocates for you in a room you weren't in.
How to Actually Lead Sideways
None of this requires a title, a mandate, or permission from anyone. A few things tend to make the difference.
Have something worth rallying around. Barta and Barwise are specific about the mechanism here: it isn’t a request or a rational case; it’s a story. A leader who wants colleagues to move with them needs a narrative compelling enough to win people over, paired with a plan. They point out something telling in their research: many of the leaders they studied were skilled at using story to move customers, yet rarely thought to use that same skill internally, with the people beside them.
A one-off favor can carry you the first time. Colleagues will often help simply because you asked, and the relationship is good. But that kind of goodwill has a limit. What sustains support is a story people want to be part of, one that makes clear why the work matters and what’s at stake if it doesn’t happen. The clearer and more compelling that story, the less you’re asking for a favor, and the more you’re engaging someone in something they already have a reason to care about.
Make the plan visible, not just the vision. Inspiration gets attention. A credible plan is what gets people to commit. Colleagues who owe you nothing are taking a real risk when they back something, their time, their standing, their own credibility, if it goes nowhere. Show them specifically what following you would look like: what you’re asking for, what you’ll deliver, and by when. Faint enthusiasm rarely survives someone’s busy week.
Start with the few, not the room. This will sound familiar if you’ve read How to Get Your Ideas Heard When You Are Not the Boss, where the same principle showed up in a different context: don’t take an untested idea straight to a large group. The mechanism is similar in this situation, but the goal is different. There, it was about getting an idea taken seriously before it faced a wider audience. Here, it’s about getting people to commit alongside you.
In practice, that means talking to two or three colleagues one-on-one before you ever raise the idea in a group setting. Not to pitch them, to think it through with them, and let them shape it before it’s finished. It is about appropriation. Hence, when the situation arises, they will be able to advocate and maybe even defend that position. That single voice, heard by others, tends to do more than a polished case made in solo.
When This Actually Happens
None of this works as a one-time initiative. You don't lead sideways for a quarter and then move on, the way you might run a specific campaign or push a single proposal through. The relationships this depends on are being shaped constantly, whether you're paying attention to them or not, in every interaction, whether you are aware of it or not.
That's really the point the research keeps circling back to. Managing up has natural checkpoints built in a performance review, a one-on-one, a moment where the relationship is formally addressed. Managing down has the same. Managing sideways has none of that. No one schedules a check-in on how your peers experience working with you (unless you are doing a 360 instituted by the organization, which is often a one-off). It either gets built deliberately, in the ordinary course of the work, or it doesn't get built at all.
In practice, that means the moments that count here are rarely the big ones. It's less about the one polished presentation and more about how you show up in the smaller exchanges around it, whether you loop a colleague in before a decision affects their work, whether you credit the person who helped shape an idea, whether you're someone people think to bring into a conversation because you've made a habit of being worth including. None of that shows up on a calendar or To Do list. It accumulates.
Managing up gets coached. Managing down gets evaluated. Managing sideways gets almost nothing. No structure, no checkpoint, no one asking how it's going,even though it is part of professional growth.
That gap is worth sitting with, not as a failure to fix, but as an opening. The colleagues beside you, who answer to no org chart that includes you, are already forming an opinion of your leadership, right now, in the ordinary course of work. The only question is whether you're shaping that deliberately or leaving it to chance.
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